diff --git a/.github/workflows/ci.py b/.github/workflows/ci.py
index 5acddd406..62f12e4e5 100644
--- a/.github/workflows/ci.py
+++ b/.github/workflows/ci.py
@@ -48,7 +48,7 @@ def install_deps():
 
 def build_kitty():
     python = shutil.which('python3') if is_bundle else sys.executable
-    cmd = '{} setup.py build --verbose'.format(python)
+    cmd = f'{python} setup.py build --verbose'
     if os.environ.get('KITTY_SANITIZE') == '1':
         cmd += ' --debug --sanitize'
     run(cmd)
@@ -59,8 +59,8 @@ def test_kitty():
 
 
 def package_kitty():
-    py = 'python3' if is_macos else 'python'
-    run(py + ' setup.py linux-package --update-check-interval=0 --verbose')
+    python = 'python3' if is_macos else 'python'
+    run(f'{python} setup.py linux-package --update-check-interval=0 --verbose')
     if is_macos:
         run('python3 setup.py kitty.app --update-check-interval=0 --verbose')
         run('kitty.app/Contents/MacOS/kitty +runpy "from kitty.constants import *; print(kitty_exe())"')
@@ -76,11 +76,11 @@ def replace_in_file(path, src, dest):
 def setup_bundle_env():
     global SW
     os.environ['SW'] = SW = '/Users/Shared/kitty-build/sw/sw' if is_macos else os.path.join(os.environ['GITHUB_WORKSPACE'], 'sw')
-    os.environ['PKG_CONFIG_PATH'] = SW + '/lib/pkgconfig'
+    os.environ['PKG_CONFIG_PATH'] = os.path.join(SW, 'lib', 'pkgconfig')
     if is_macos:
         os.environ['PATH'] = '{}:{}'.format('/usr/local/opt/sphinx-doc/bin', os.environ['PATH'])
     else:
-        os.environ['LD_LIBRARY_PATH'] = SW + '/lib'
+        os.environ['LD_LIBRARY_PATH'] = os.path.join(SW, 'lib')
         os.environ['PYTHONHOME'] = SW
     os.environ['PATH'] = '{}:{}'.format(os.path.join(SW, 'bin'), os.environ['PATH'])
 
@@ -111,7 +111,7 @@ def main():
         setup_bundle_env()
     else:
         if not is_macos and 'pythonLocation' in os.environ:
-            os.environ['LD_LIBRARY_PATH'] = '{}/lib'.format(os.environ['pythonLocation'])
+            os.environ['LD_LIBRARY_PATH'] = os.path.join(os.environ['pythonLocation'], 'lib')
     action = sys.argv[-1]
     if action in ('build', 'package'):
         install_deps()
@@ -122,7 +122,7 @@ def main():
     elif action == 'test':
         test_kitty()
     else:
-        raise SystemExit('Unknown action: ' + action)
+        raise SystemExit(f'Unknown action: {action}')
 
 
 if __name__ == '__main__':
diff --git a/build-terminfo b/build-terminfo
index 3fbae33b5..25bbc50bc 100755
--- a/build-terminfo
+++ b/build-terminfo
@@ -13,7 +13,7 @@ import tempfile
 
 def compile_terminfo(base):
     with tempfile.TemporaryDirectory() as tdir:
-        proc = subprocess.run(['tic', '-x', '-o' + tdir, 'terminfo/kitty.terminfo'], check=True, stderr=subprocess.PIPE)
+        proc = subprocess.run(['tic', '-x', f'-o{tdir}', 'terminfo/kitty.terminfo'], check=True, stderr=subprocess.PIPE)
         regex = '^"terminfo/kitty.terminfo", line [0-9]+, col [0-9]+, terminal \'xterm-kitty\': older tic versions may treat the description field as an alias$'
         for error in proc.stderr.decode('utf-8').splitlines():
             if not re.match(regex, error):
diff --git a/bypy/init_env.py b/bypy/init_env.py
index 02ae0ca04..1678d90bc 100644
--- a/bypy/init_env.py
+++ b/bypy/init_env.py
@@ -26,7 +26,7 @@ def initialize_constants():
     kitty_constants = {}
     src = read_src_file('constants.py')
     nv = re.search(r'Version\((\d+), (\d+), (\d+)\)', src)
-    kitty_constants['version'] = '%s.%s.%s' % (nv.group(1), nv.group(2), nv.group(3))
+    kitty_constants['version'] = f'{nv.group(1)}.{nv.group(2)}.{nv.group(3)}'
     kitty_constants['appname'] = re.search(
             r'appname: str\s+=\s+(u{0,1})[\'"]([^\'"]+)[\'"]', src
     ).group(2)
diff --git a/bypy/linux/__main__.py b/bypy/linux/__main__.py
index 5dde2c911..b89518f1d 100644
--- a/bypy/linux/__main__.py
+++ b/bypy/linux/__main__.py
@@ -38,7 +38,7 @@ def binary_includes():
             'ncursesw', 'readline', 'brotlicommon', 'brotlienc', 'brotlidec'
         ))) + (
                 get_dll_path('bz2', 2), get_dll_path('ssl', 2), get_dll_path('crypto', 2),
-                get_dll_path('python' + py_ver, 2),
+                get_dll_path(f'python{py_ver}', 2),
         )
 
 
@@ -47,7 +47,7 @@ class Env:
     def __init__(self, package_dir):
         self.base = package_dir
         self.lib_dir = j(self.base, 'lib')
-        self.py_dir = j(self.lib_dir, 'python' + py_ver)
+        self.py_dir = j(self.lib_dir, f'python{py_ver}')
         os.makedirs(self.py_dir)
         self.bin_dir = j(self.base, 'bin')
         self.obj_dir = mkdtemp('launchers-')
@@ -107,7 +107,7 @@ def add_ca_certs(env):
 
 def copy_python(env):
     print('Copying python...')
-    srcdir = j(PREFIX, 'lib/python' + py_ver)
+    srcdir = j(PREFIX, f'lib/python{py_ver}')
 
     for x in os.listdir(srcdir):
         y = j(srcdir, x)
@@ -187,11 +187,11 @@ def strip_files(files, argv_max=(256 * 1024)):
 
 
 def strip_binaries(files):
-    print('Stripping %d files...' % len(files))
+    print(f'Stripping {len(files)} files...')
     before = sum(os.path.getsize(x) for x in files)
     strip_files(files)
     after = sum(os.path.getsize(x) for x in files)
-    print('Stripped %.1f MB' % ((before - after) / (1024 * 1024.)))
+    print('Stripped {:.1f} MB'.format((before - after) / (1024 * 1024.)))
 
 
 def create_tarfile(env, compression_level='9'):
@@ -203,7 +203,7 @@ def create_tarfile(env, compression_level='9'):
         if err.errno != errno.ENOENT:
             raise
     os.mkdir(base)
-    dist = os.path.join(base, '%s-%s-%s.tar' % (kitty_constants['appname'], kitty_constants['version'], arch))
+    dist = os.path.join(base, f'{kitty_constants["appname"]}-{kitty_constants["version"]}-{arch}.tar')
     with tarfile.open(dist, mode='w', format=tarfile.PAX_FORMAT) as tf:
         cwd = os.getcwd()
         os.chdir(env.base)
@@ -213,13 +213,13 @@ def create_tarfile(env, compression_level='9'):
         finally:
             os.chdir(cwd)
     print('Compressing archive...')
-    ans = dist.rpartition('.')[0] + '.txz'
+    ans = f'{dist.rpartition(".")[0]}.txz'
     start_time = time.time()
-    subprocess.check_call(['xz', '--threads=0', '-f', '-' + compression_level, dist])
+    subprocess.check_call(['xz', '--threads=0', '-f', f'-{compression_level}', dist])
     secs = time.time() - start_time
-    print('Compressed in %d minutes %d seconds' % (secs // 60, secs % 60))
-    os.rename(dist + '.xz', ans)
-    print('Archive %s created: %.2f MB' % (
+    print('Compressed in {} minutes {} seconds'.format(secs // 60, secs % 60))
+    os.rename(f'{dist}.xz', ans)
+    print('Archive {} created: {:.2f} MB'.format(
         os.path.basename(ans), os.stat(ans).st_size / (1024.**2)))
 
 
diff --git a/bypy/macos/__main__.py b/bypy/macos/__main__.py
index 15e5fbe29..e21eb924b 100644
--- a/bypy/macos/__main__.py
+++ b/bypy/macos/__main__.py
@@ -90,7 +90,7 @@ def strip_files(files, argv_max=(256 * 1024)):
 def files_in(folder):
     for record in os.walk(folder):
         for f in record[-1]:
-            yield os.path.join(record[0], f)
+            yield join(record[0], f)
 
 
 def expand_dirs(items, exclude=lambda x: x.endswith('.so')):
@@ -103,7 +103,7 @@ def expand_dirs(items, exclude=lambda x: x.endswith('.so')):
 
 
 def do_sign(app_dir):
-    with current_dir(os.path.join(app_dir, 'Contents')):
+    with current_dir(join(app_dir, 'Contents')):
         # Sign all .so files
         so_files = {x for x in files_in('.') if x.endswith('.so')}
         codesign(so_files)
@@ -153,7 +153,7 @@ class Freeze(object):
         self.to_strip = []
         self.warnings = []
         self.py_ver = py_ver
-        self.python_stdlib = join(self.resources_dir, 'Python', 'lib', 'python' + self.py_ver)
+        self.python_stdlib = join(self.resources_dir, 'Python', 'lib', f'python{self.py_ver}')
         self.site_packages = self.python_stdlib  # hack to avoid needing to add site-packages to path
         self.obj_dir = mkdtemp('launchers-')
 
@@ -177,7 +177,7 @@ class Freeze(object):
             self.run_tests()
         # self.run_shell()
 
-        ret = self.makedmg(self.build_dir, APPNAME + '-' + VERSION)
+        ret = self.makedmg(self.build_dir, f'{APPNAME}-{VERSION}')
 
         return ret
 
@@ -186,7 +186,7 @@ class Freeze(object):
         print('\nDownloading CA certs...')
         from urllib.request import urlopen
         cdata = urlopen(kitty_constants['cacerts_url']).read()
-        dest = os.path.join(self.contents_dir, 'Resources', 'cacert.pem')
+        dest = join(self.contents_dir, 'Resources', 'cacert.pem')
         with open(dest, 'wb') as f:
             f.write(cdata)
 
@@ -197,7 +197,7 @@ class Freeze(object):
 
     @flush
     def run_tests(self):
-        iv['run_tests'](os.path.join(self.contents_dir, 'MacOS', 'kitty'))
+        iv['run_tests'](join(self.contents_dir, 'MacOS', 'kitty'))
 
     @flush
     def set_id(self, path_to_lib, new_id):
@@ -222,10 +222,10 @@ class Freeze(object):
     @flush
     def get_local_dependencies(self, path_to_lib):
         for x, is_id in self.get_dependencies(path_to_lib):
-            for y in (PREFIX + '/lib/', PREFIX + '/python/Python.framework/', '@rpath/'):
+            for y in (f'{PREFIX}/lib/', f'{PREFIX}/python/Python.framework/', '@rpath/'):
                 if x.startswith(y):
-                    if y == PREFIX + '/python/Python.framework/':
-                        y = PREFIX + '/python/'
+                    if y == f'{PREFIX}/python/Python.framework/':
+                        y = f'{PREFIX}/python/'
                     yield x, x[len(y):], is_id
                     break
 
@@ -239,7 +239,7 @@ class Freeze(object):
         self.to_strip.append(path_to_lib)
         old_mode = flipwritable(path_to_lib)
         for dep, bname, is_id in self.get_local_dependencies(path_to_lib):
-            ndep = self.FID + '/' + bname
+            ndep = f'{self.FID}/{bname}'
             self.change_dep(dep, ndep, is_id, path_to_lib)
         ldeps = list(self.get_local_dependencies(path_to_lib))
         if ldeps:
@@ -252,7 +252,7 @@ class Freeze(object):
     @flush
     def add_python_framework(self):
         print('\nAdding Python framework')
-        src = join(PREFIX + '/python', 'Python.framework')
+        src = join(f'{PREFIX}/python', 'Python.framework')
         x = join(self.frameworks_dir, 'Python.framework')
         curr = os.path.realpath(join(src, 'Versions', 'Current'))
         currd = join(x, 'Versions', basename(curr))
@@ -262,12 +262,12 @@ class Freeze(object):
         shutil.copy2(join(curr, 'Python'), currd)
         self.set_id(
             join(currd, 'Python'),
-            self.FID + '/Python.framework/Versions/%s/Python' % basename(curr))
+            f'{self.FID}/Python.framework/Versions/{basename(curr)}/Python')
         # The following is needed for codesign
         with current_dir(x):
             os.symlink(basename(curr), 'Versions/Current')
             for y in ('Python', 'Resources'):
-                os.symlink('Versions/Current/%s' % y, y)
+                os.symlink(f'Versions/Current/{y}', y)
 
     @flush
     def install_dylib(self, path, set_id=True):
@@ -275,7 +275,7 @@ class Freeze(object):
         if set_id:
             self.set_id(
                 join(self.frameworks_dir, basename(path)),
-                self.FID + '/' + basename(path))
+                f'{self.FID}/{basename(path)}')
         self.fix_dependencies_in_lib(join(self.frameworks_dir, basename(path)))
 
     @flush
@@ -291,11 +291,11 @@ class Freeze(object):
                 'rsync.2',
         ):
             print('\nAdding', x)
-            x = 'lib%s.dylib' % x
+            x = f'lib{x}.dylib'
             src = join(PREFIX, 'lib', x)
             shutil.copy2(src, self.frameworks_dir)
             dest = join(self.frameworks_dir, x)
-            self.set_id(dest, self.FID + '/' + x)
+            self.set_id(dest, f'{self.FID}/{x}')
             self.fix_dependencies_in_lib(dest)
 
     @flush
@@ -321,7 +321,7 @@ class Freeze(object):
     @flush
     def add_stdlib(self):
         print('\nAdding python stdlib')
-        src = PREFIX + '/python/Python.framework/Versions/Current/lib/python' + self.py_ver
+        src = f'{PREFIX}/python/Python.framework/Versions/Current/lib/python{self.py_ver}'
         dest = self.python_stdlib
         if not os.path.exists(dest):
             os.makedirs(dest)
@@ -345,19 +345,19 @@ class Freeze(object):
         kitty_dir = join(self.resources_dir, 'kitty')
         bases = ('kitty', 'kittens', 'kitty_tests')
         for x in bases:
-            dest = os.path.join(self.python_stdlib, x)
-            os.rename(os.path.join(kitty_dir, x), dest)
+            dest = join(self.python_stdlib, x)
+            os.rename(join(kitty_dir, x), dest)
             if x == 'kitty':
-                shutil.rmtree(os.path.join(dest, 'launcher'))
-        os.rename(os.path.join(kitty_dir, '__main__.py'), os.path.join(self.python_stdlib, 'kitty_main.py'))
-        shutil.rmtree(os.path.join(kitty_dir, '__pycache__'))
-        pdir = os.path.join(dirname(self.python_stdlib), 'kitty-extensions')
+                shutil.rmtree(join(dest, 'launcher'))
+        os.rename(join(kitty_dir, '__main__.py'), join(self.python_stdlib, 'kitty_main.py'))
+        shutil.rmtree(join(kitty_dir, '__pycache__'))
+        pdir = join(dirname(self.python_stdlib), 'kitty-extensions')
         os.mkdir(pdir)
         print('Extracting extension modules from', self.python_stdlib, 'to', pdir)
         ext_map = extract_extension_modules(self.python_stdlib, pdir)
-        shutil.copy(os.path.join(os.path.dirname(self_dir), 'site.py'), os.path.join(self.python_stdlib, 'site.py'))
+        shutil.copy(join(os.path.dirname(self_dir), 'site.py'), join(self.python_stdlib, 'site.py'))
         for x in bases:
-            iv['sanitize_source_folder'](os.path.join(self.python_stdlib, x))
+            iv['sanitize_source_folder'](join(self.python_stdlib, x))
         self.compile_py_modules()
         freeze_python(self.python_stdlib, pdir, self.obj_dir, ext_map, develop_mode_env_var='KITTY_DEVELOP_FROM', remove_pyc_files=True)
         iv['build_frozen_launcher']([path_to_freeze_dir(), self.obj_dir])
@@ -434,23 +434,23 @@ class Freeze(object):
         ''' Copy a directory d into a dmg named volname '''
         print('\nMaking dmg...')
         sys.stdout.flush()
-        destdir = os.path.join(SW, 'dist')
+        destdir = join(SW, 'dist')
         try:
             shutil.rmtree(destdir)
         except FileNotFoundError:
             pass
         os.mkdir(destdir)
-        dmg = os.path.join(destdir, volname + '.dmg')
+        dmg = join(destdir, f'{volname}.dmg')
         if os.path.exists(dmg):
             os.unlink(dmg)
         tdir = tempfile.mkdtemp()
-        appdir = os.path.join(tdir, os.path.basename(d))
+        appdir = join(tdir, os.path.basename(d))
         shutil.copytree(d, appdir, symlinks=True)
         if self.sign_installers:
             with timeit() as times:
                 sign_app(appdir, self.notarize)
-            print('Signing completed in %d minutes %d seconds' % tuple(times))
-        os.symlink('/Applications', os.path.join(tdir, 'Applications'))
+            print('Signing completed in {} minutes {} seconds'.format(*times))
+        os.symlink('/Applications', join(tdir, 'Applications'))
         size_in_mb = int(
             subprocess.check_output(['du', '-s', '-k', tdir]).decode('utf-8')
             .split()[0]) / 1024.
@@ -466,10 +466,10 @@ class Freeze(object):
         print('\nCreating dmg...')
         with timeit() as times:
             subprocess.check_call(cmd + [dmg])
-        print('dmg created in %d minutes and %d seconds' % tuple(times))
+        print('dmg created in {} minutes and {} seconds'.format(*times))
         shutil.rmtree(tdir)
         size = os.stat(dmg).st_size / (1024 * 1024.)
-        print('\nInstaller size: %.2fMB\n' % size)
+        print(f'\nInstaller size: {size:.2f}MB\n')
         return dmg
 
 
@@ -477,7 +477,7 @@ def main():
     args = globals()['args']
     ext_dir = globals()['ext_dir']
     Freeze(
-        os.path.join(ext_dir, kitty_constants['appname'] + '.app'),
+        join(ext_dir, f'{kitty_constants["appname"]}.app'),
         dont_strip=args.dont_strip,
         sign_installers=args.sign_installers,
         notarize=args.notarize,
diff --git a/docs/conf.py b/docs/conf.py
index fc6d621a7..c0a95b913 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -13,7 +13,7 @@ import subprocess
 import sys
 import time
 from functools import partial
-from typing import Any, Callable, Dict, Iterable, List, Match, Optional, Tuple
+from typing import Any, Callable, Dict, Iterable, List, Optional, Tuple
 
 from docutils import nodes
 from docutils.parsers.rst.roles import set_classes
@@ -28,7 +28,7 @@ kitty_src = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
 if kitty_src not in sys.path:
     sys.path.insert(0, kitty_src)
 
-from kitty.conf.types import Definition  # noqa
+from kitty.conf.types import Definition, expand_opt_references  # noqa
 from kitty.constants import str_version, website_url  # noqa
 
 # config {{{
@@ -217,7 +217,8 @@ if you specify a program-to-run you can use the special placeholder
     from kitty.remote_control import cli_msg, global_options_spec
     with open('generated/cli-kitty-at.rst', 'w') as f:
         p = partial(print, file=f)
-        p('kitty @\n' + '-' * 80)
+        p('kitty @')
+        p('-' * 80)
         p('.. program::', 'kitty @')
         p('\n\n' + as_rst(
             global_options_spec, message=cli_msg, usage='command ...', appname='kitty @'))
@@ -225,7 +226,8 @@ if you specify a program-to-run you can use the special placeholder
         for cmd_name in sorted(all_command_names()):
             func = command_for_name(cmd_name)
             p(f'.. _at_{func.name}:\n')
-            p('kitty @', func.name + '\n' + '-' * 120)
+            p('kitty @', func.name)
+            p('-' * 120)
             p('.. program::', 'kitty @', func.name)
             p('\n\n' + as_rst(*cli_params_for(func)))
     from kittens.runner import get_kitten_cli_docs
@@ -234,12 +236,12 @@ if you specify a program-to-run you can use the special placeholder
         if data:
             with open(f'generated/cli-kitten-{kitten}.rst', 'w') as f:
                 p = partial(print, file=f)
-                p('.. program::', f'kitty +kitten {kitten}')
-                p(f'\nSource code for {kitten}')
+                p('.. program::', 'kitty +kitten', kitten)
+                p('\nSource code for', kitten)
                 p('-' * 72)
                 p(f'\nThe source code for this kitten is `available on GitHub <https://github.com/kovidgoyal/kitty/tree/master/kittens/{kitten}>`_.')
                 p('\nCommand Line Interface')
-                p('-' * 72, file=f)
+                p('-' * 72)
                 p('\n\n' + option_spec_as_rst(
                     data['options'], message=data['help_text'], usage=data['usage'], appname=f'kitty +kitten {kitten}',
                     heading_char='^'))
@@ -364,19 +366,6 @@ def link_role(
     return [node], []
 
 
-def expand_opt_references(conf_name: str, text: str) -> str:
-    conf_name += '.'
-
-    def expand(m: Match[str]) -> str:
-        ref = m.group(1)
-        if '<' not in ref and '.' not in ref:
-            full_ref = conf_name + ref
-            return f':opt:`{ref} <{full_ref}>`'
-        return str(m.group())
-
-    return re.sub(r':opt:`(.+?)`', expand, text)
-
-
 opt_aliases: Dict[str, str] = {}
 shortcut_slugs: Dict[str, Tuple[str, str]] = {}
 
@@ -414,7 +403,7 @@ def process_opt_link(env: Any, refnode: Any, has_explicit_title: bool, title: st
     conf_name, opt = target.partition('.')[::2]
     if not opt:
         conf_name, opt = 'kitty', conf_name
-    full_name = conf_name + '.' + opt
+    full_name = f'{conf_name}.{opt}'
     return title, opt_aliases.get(full_name, full_name)
 
 
@@ -422,7 +411,7 @@ def process_shortcut_link(env: Any, refnode: Any, has_explicit_title: bool, titl
     conf_name, slug = target.partition('.')[::2]
     if not slug:
         conf_name, slug = 'kitty', conf_name
-    full_name = conf_name + '.' + slug
+    full_name = f'{conf_name}.{slug}'
     try:
         target, stitle = shortcut_slugs[full_name]
     except KeyError:
diff --git a/gen-apc-parsers.py b/gen-apc-parsers.py
index 67067101a..241209a62 100755
--- a/gen-apc-parsers.py
+++ b/gen-apc-parsers.py
@@ -1,6 +1,7 @@
 #!/usr/bin/env python3
 # License: GPLv3 Copyright: 2018, Kovid Goyal <kovid at kovidgoyal.net>
 
+import os
 import subprocess
 from collections import defaultdict
 from typing import Any, DefaultDict, Dict, FrozenSet, List, Tuple, Union
@@ -42,7 +43,7 @@ def parse_flag(keymap: KeymapType, type_map: Dict[str, Any], command_class: str)
     lines = []
     for ch in type_map['flag']:
         attr, allowed_values = keymap[ch]
-        q = ' && '.join(f"g.{attr} != '{x}'" for x in allowed_values)
+        q = ' && '.join(f"g.{attr} != '{x}'" for x in sorted(allowed_values))
         lines.append(f'''
             case {attr}: {{
                 g.{attr} = screen->parser_buf[pos++] & 0xff;
@@ -67,7 +68,7 @@ def cmd_for_report(report_name: str, keymap: KeymapType, type_map: Dict[str, Any
         flag_fmt, flag_attrs = [], []
         cv = {'flag': 'c', 'int': 'i', 'uint': 'I'}[atype]
         for ch in type_map[atype]:
-            flag_fmt.append('s' + cv)
+            flag_fmt.append(f's{cv}')
             attr = keymap[ch][0]
             flag_attrs.append(f'"{attr}", {conv}g.{attr}')
         return ' '.join(flag_fmt), ', '.join(flag_attrs)
@@ -240,7 +241,7 @@ static inline void
 
 def write_header(text: str, path: str) -> None:
     with open(path, 'w') as f:
-        print(f'// This file is generated by {__file__} do not edit!', file=f, end='\n\n')
+        print(f'// This file is generated by {os.path.basename(__file__)} do not edit!', file=f, end='\n\n')
         print('#pragma once', file=f)
         print(text, file=f)
     subprocess.check_call(['clang-format', '-i', path])
diff --git a/gen-key-constants.py b/gen-key-constants.py
index 81e366f85..f52050be1 100755
--- a/gen-key-constants.py
+++ b/gen-key-constants.py
@@ -238,7 +238,7 @@ def patch_file(path: str, what: str, text: str, start_marker: str = '/* ', end_m
             end = raw.index(end_q)
         except ValueError:
             raise SystemExit(f'Failed to find "{end_q}" in {path}')
-        raw = raw[:start] + start_q + '\n' + text + '\n' + raw[end:]
+        raw = f'{raw[:start]}{start_q}\n{text}\n{raw[end:]}'
         f.seek(0)
         f.truncate(0)
         f.write(raw)
@@ -368,7 +368,7 @@ def generate_ctrl_mapping() -> None:
         val = str(ctrl_mapping[k])
         items.append(val)
         if k in "\\'":
-            k = '\\' + k
+            k = f'\\{k}'
         mi.append(f"        case '{k}': return {val};")
 
     for line_items in chunks(items, 6):
diff --git a/glfw/glfw.py b/glfw/glfw.py
index 6cfb89650..e7a5cf0c7 100755
--- a/glfw/glfw.py
+++ b/glfw/glfw.py
@@ -80,7 +80,7 @@ def init_env(
 ) -> Env:
     ans = env.copy()
     ans.cflags.append('-fPIC')
-    ans.cppflags.append('-D_GLFW_' + module.upper())
+    ans.cppflags.append(f'-D_GLFW_{module.upper()}')
     ans.cppflags.append('-D_GLFW_BUILD_DLL')
 
     with open(os.path.join(base, 'source-info.json')) as f:
diff --git a/kittens/diff/collect.py b/kittens/diff/collect.py
index 2380de75c..104f8ee11 100644
--- a/kittens/diff/collect.py
+++ b/kittens/diff/collect.py
@@ -101,7 +101,7 @@ def remote_hostname(path: str) -> Tuple[Optional[str], Optional[str]]:
 def resolve_remote_name(path: str, default: str) -> str:
     remote_dir, rh = remote_hostname(path)
     if remote_dir and rh:
-        return rh + ':' + os.path.relpath(path, remote_dir)
+        return f'{rh}:{os.path.relpath(path, remote_dir)}'
     return default
 
 
diff --git a/kittens/diff/highlight.py b/kittens/diff/highlight.py
index 968b195b3..0a1eb502d 100644
--- a/kittens/diff/highlight.py
+++ b/kittens/diff/highlight.py
@@ -97,7 +97,7 @@ def highlight_data(code: str, filename: str, aliases: Optional[Dict[str, str]] =
         base, ext = os.path.splitext(filename)
         alias = aliases.get(ext[1:])
         if alias is not None:
-            filename = base + '.' + alias
+            filename = f'{base}.{alias}'
     try:
         lexer = get_lexer_for_filename(filename, stripnl=False)
     except ClassNotFound:
diff --git a/kittens/diff/main.py b/kittens/diff/main.py
index c5282f85e..16e00efa0 100644
--- a/kittens/diff/main.py
+++ b/kittens/diff/main.py
@@ -347,7 +347,7 @@ class DiffHandler(Handler):
                 text = line.text
                 if line.image_data is not None:
                     image_involved = True
-            self.write('\r\x1b[K' + text + '\x1b[0m')
+            self.write(f'\r\x1b[K{text}\x1b[0m')
             if self.current_search is not None:
                 self.current_search.highlight_line(self.write, lpos)
             if i < num - 1:
@@ -465,7 +465,7 @@ class DiffHandler(Handler):
                 )
             else:
                 counts = styled(f'{len(self.current_search)} matches', fg=self.opts.margin_fg)
-            suffix = counts + '  ' + scroll_frac
+            suffix = f'{counts}  {scroll_frac}'
             prefix = styled(':', fg=self.opts.margin_fg)
             filler = self.screen_size.cols - wcswidth(prefix) - wcswidth(suffix)
             text = '{}{}{}'.format(prefix, ' ' * filler, suffix)
diff --git a/kittens/diff/patch.py b/kittens/diff/patch.py
index 0042af76e..44c777a76 100644
--- a/kittens/diff/patch.py
+++ b/kittens/diff/patch.py
@@ -244,14 +244,14 @@ class Differ:
             except Exception as e:
                 return f'Running git diff for {left_path} vs. {right_path} generated an exception: {e}'
             if not ok:
-                return output + f'\nRunning git diff for {left_path} vs. {right_path} failed'
+                return f'{output}\nRunning git diff for {left_path} vs. {right_path} failed'
             left_lines = lines_for_path(left_path)
             right_lines = lines_for_path(right_path)
             try:
                 patch = parse_patch(output)
             except Exception:
                 import traceback
-                return traceback.format_exc() + f'\nParsing diff for {left_path} vs. {right_path} failed'
+                return f'{traceback.format_exc()}\nParsing diff for {left_path} vs. {right_path} failed'
             else:
                 ans[key] = patch
         return ans
diff --git a/kittens/diff/render.py b/kittens/diff/render.py
index 5b29b0f71..6e6cbdf13 100644
--- a/kittens/diff/render.py
+++ b/kittens/diff/render.py
@@ -101,7 +101,7 @@ def human_readable(size: int, sep: str = ' ') -> str:
         s = s[:s.find(".")+2]
     if s.endswith('.0'):
         s = s[:-2]
-    return s + sep + suffix
+    return f'{s}{sep}{suffix}'
 
 
 def fit_in(text: str, count: int) -> str:
@@ -110,7 +110,7 @@ def fit_in(text: str, count: int) -> str:
         return text
     if count > 1:
         p = truncate_point_for_length(text, count - 1)
-    return text[:p] + '…'
+    return f'{text[:p]}…'
 
 
 def fill_in(text: str, sz: int) -> str:
@@ -127,8 +127,8 @@ def place_in(text: str, sz: int) -> str:
 def format_func(which: str) -> Callable[[str], str]:
     def formatted(text: str) -> str:
         fmt = formats[which]
-        return '\x1b[' + fmt + 'm' + text + '\x1b[0m'
-    formatted.__name__ = which + '_format'
+        return f'\x1b[{fmt}m{text}\x1b[0m'
+    formatted.__name__ = f'{which}_format'
     return formatted
 
 
@@ -148,8 +148,8 @@ highlight_map = {'remove': ('removed_highlight', 'removed'), 'add': ('added_high
 
 def highlight_boundaries(ltype: str) -> Tuple[str, str]:
     s, e = highlight_map[ltype]
-    start = '\x1b[' + formats[s] + 'm'
-    stop = '\x1b[' + formats[e] + 'm'
+    start = f'\x1b[{formats[s]}m'
+    stop = f'\x1b[{formats[e]}m'
     return start, stop
 
 
diff --git a/kittens/hints/main.py b/kittens/hints/main.py
index df2e7fe01..6acf9e292 100644
--- a/kittens/hints/main.py
+++ b/kittens/hints/main.py
@@ -729,7 +729,7 @@ def linenum_handle_result(args: List[str], data: Dict[str, Any], target_window_i
             else:
                 import shlex
                 text = ' '.join(shlex.quote(arg) for arg in cmd)
-                w.paste_bytes(text + '\r')
+                w.paste_bytes(f'{text}\r')
     elif action == 'background':
         import subprocess
         subprocess.Popen(cmd, cwd=data['cwd'])
diff --git a/kittens/query_terminal/main.py b/kittens/query_terminal/main.py
index b7d518710..22aeb2b7d 100644
--- a/kittens/query_terminal/main.py
+++ b/kittens/query_terminal/main.py
@@ -245,7 +245,7 @@ def main(args: List[str] = sys.argv) -> None:
             raise SystemExit(f'Unknown queries: {", ".join(extra)}')
 
     for key, val in do_queries(queries, cli_opts).items():
-        print(key + ':', val)
+        print(f'{key}:', val)
 
 
 if __name__ == '__main__':
diff --git a/kittens/show_key/kitty_mode.py b/kittens/show_key/kitty_mode.py
index a1113440d..369a8c46d 100644
--- a/kittens/show_key/kitty_mode.py
+++ b/kittens/show_key/kitty_mode.py
@@ -52,7 +52,7 @@ class KeysHandler(Handler):
         self.cmd.colored(etype + ' ', 'yellow')
         self.cmd.styled(key_event.text, italic=True)
         self.print()
-        rep = 'CSI ' + encode_key_event(key_event)[2:]
+        rep = f'CSI {encode_key_event(key_event)[2:]}'
         rep = rep.replace(';', ' ; ').replace(':', ' : ')[:-1] + ' ' + rep[-1]
         self.cmd.styled(rep, fg='magenta')
         if (key_event.shifted_key or key_event.alternate_key):
diff --git a/kittens/show_key/main.py b/kittens/show_key/main.py
index 635074ea0..e4ba18e49 100644
--- a/kittens/show_key/main.py
+++ b/kittens/show_key/main.py
@@ -17,7 +17,7 @@ def print_key(raw: bytearray) -> None:
     unix = ''
     for ch in raw:
         if ch < len(ctrl_keys):
-            unix += '^' + ctrl_keys[ch]
+            unix += f'^{ctrl_keys[ch]}'
         elif ch == 127:
             unix += '^?'
         else:
diff --git a/kittens/ssh/completion.py b/kittens/ssh/completion.py
index ff97c6bd9..6ac079263 100644
--- a/kittens/ssh/completion.py
+++ b/kittens/ssh/completion.py
@@ -281,7 +281,7 @@ def complete_choices(ans: Completions, prefix: str, title: str, choices: Iterabl
         if q.startswith(effective_prefix):
             if comma_separated:
                 tq = q
-                q = hidden_prefix + q + ','
+                q = f'{hidden_prefix}{q},'
                 word_transforms[q] = tq
             matches[q] = ''
     ans.add_match_group(title, matches, trailing_space=not comma_separated, word_transforms=word_transforms)
diff --git a/kittens/ssh/main.py b/kittens/ssh/main.py
index 5e286a29e..da5e022f9 100644
--- a/kittens/ssh/main.py
+++ b/kittens/ssh/main.py
@@ -131,7 +131,7 @@ def get_ssh_cli() -> Tuple[Set[str], Set[str]]:
     other_ssh_args: Set[str] = set()
     boolean_ssh_args: Set[str] = set()
     for k, v in ssh_options().items():
-        k = '-' + k
+        k = f'-{k}'
         if v:
             other_ssh_args.add(k)
         else:
@@ -213,7 +213,7 @@ class InvalidSSHArgs(ValueError):
 
 def parse_ssh_args(args: List[str]) -> Tuple[List[str], List[str], bool]:
     boolean_ssh_args, other_ssh_args = get_ssh_cli()
-    passthrough_args = {'-' + x for x in 'Nnf'}
+    passthrough_args = {f'-{x}' for x in 'Nnf'}
     ssh_args = []
     server_args: List[str] = []
     expecting_option_val = False
@@ -230,7 +230,7 @@ def parse_ssh_args(args: List[str]) -> Tuple[List[str], List[str], bool]:
             # could be a multi-character option
             all_args = argument[1:]
             for i, arg in enumerate(all_args):
-                arg = '-' + arg
+                arg = f'-{arg}'
                 if arg in passthrough_args:
                     passthrough = True
                 if arg in boolean_ssh_args:
diff --git a/kittens/themes/collection.py b/kittens/themes/collection.py
index 2b8c5935e..c7d24e79a 100644
--- a/kittens/themes/collection.py
+++ b/kittens/themes/collection.py
@@ -376,7 +376,7 @@ def fetch_themes(
 
     needs_delete = False
     try:
-        with tempfile.NamedTemporaryFile(suffix='-' + os.path.basename(dest_path), dir=os.path.dirname(dest_path), delete=False) as f:
+        with tempfile.NamedTemporaryFile(suffix=f'-{os.path.basename(dest_path)}', dir=os.path.dirname(dest_path), delete=False) as f:
             needs_delete = True
             shutil.copyfileobj(res, f)
             f.flush()
@@ -405,7 +405,7 @@ def theme_name_from_file_name(fname: str) -> str:
     ans = ans.replace('_', ' ')
 
     def camel_case(m: 'Match[str]') -> str:
-        return str(m.group(1) + ' ' + m.group(2))
+        return f'{m.group(1)} {m.group(2)}'
 
     ans = re.sub(r'([a-z])([A-Z])', camel_case, ans)
     return ' '.join(x.capitalize() for x in filter(None, ans.split()))
@@ -533,7 +533,7 @@ class Theme:
             raw = ''
         nraw = patch_conf(raw, self.name)
         if raw:
-            with open(confpath + '.bak', 'w') as f:
+            with open(f'{confpath}.bak', 'w') as f:
                 f.write(raw)
         atomic_save(nraw.encode('utf-8'), confpath)
         if reload_in == 'parent':
diff --git a/kittens/themes/main.py b/kittens/themes/main.py
index 48024bf1c..68ea6b0f8 100644
--- a/kittens/themes/main.py
+++ b/kittens/themes/main.py
@@ -37,7 +37,7 @@ def limit_length(text: str, limit: int = 32) -> str:
     x = truncate_point_for_length(text, limit - 1)
     if x >= len(text):
         return text
-    return text[:x] + '…'
+    return f'{text[:x]}…'
 
 
 class State(Enum):
@@ -332,7 +332,7 @@ class ThemesHandler(Handler):
         for line, width, is_current in self.themes_list.lines(num_rows):
             num_rows -= 1
             if is_current:
-                line = line.replace(MARK_AFTER, '\033[' + color_code('green') + 'm')
+                line = line.replace(MARK_AFTER, f'\033[{color_code("green")}m')
             self.cmd.styled('>' if is_current else ' ', fg='green')
             self.cmd.styled(line, bold=is_current, fg='green' if is_current else None)
             self.cmd.move_cursor_by(mw - width, 'right')
diff --git a/kittens/transfer/librsync.py b/kittens/transfer/librsync.py
index 1f951323d..21d9feed2 100644
--- a/kittens/transfer/librsync.py
+++ b/kittens/transfer/librsync.py
@@ -155,12 +155,12 @@ def develop() -> None:
     import sys
     src = sys.argv[-1]
     sig_loader = LoadSignature()
-    with open(src + '.sig', 'wb') as f:
+    with open(f'{src}.sig', 'wb') as f:
         for chunk in signature_of_file(src):
             sig_loader.add_chunk(chunk)
             f.write(chunk)
     sig_loader.commit()
-    with open(src + '.delta', 'wb') as f, PatchFile(src, src + '.output') as patcher:
+    with open(f'{src}.delta', 'wb') as f, PatchFile(src, f'{src}.output') as patcher:
         for chunk in delta_for_file(src, sig_loader.signature):
             f.write(chunk)
             patcher.write(chunk)
diff --git a/kittens/transfer/utils.py b/kittens/transfer/utils.py
index 54ed9589e..fa55b63a8 100644
--- a/kittens/transfer/utils.py
+++ b/kittens/transfer/utils.py
@@ -45,7 +45,7 @@ def render_path_in_width(path: str, width: int) -> str:
     if wcswidth(path) <= width:
         return path
     x = truncate_point_for_length(path, width - 1)
-    return path[:x] + '…'
+    return f'{path[:x]}…'
 
 
 def render_seconds(val: float) -> str:
diff --git a/kittens/tui/dircolors.py b/kittens/tui/dircolors.py
index 6d0fd304e..804b865ca 100644
--- a/kittens/tui/dircolors.py
+++ b/kittens/tui/dircolors.py
@@ -331,7 +331,7 @@ class Dircolors:
                 # change .xyz to *.xyz
                 yield '*' + pair[0], pair[1]
 
-        return ':'.join('%s=%s' % pair for pair in gen_pairs())
+        return ':'.join('{}={}'.format(*pair) for pair in gen_pairs())
 
     def _format_code(self, text: str, code: str) -> str:
         val = self.codes.get(code)
diff --git a/kittens/tui/operations.py b/kittens/tui/operations.py
index 308e758ed..add55d472 100644
--- a/kittens/tui/operations.py
+++ b/kittens/tui/operations.py
@@ -163,7 +163,7 @@ def set_scrolling_region(screen_size: Optional['ScreenSize'] = None, top: Option
 
 @cmd
 def scroll_screen(amt: int = 1) -> str:
-    return '\033[' + str(abs(amt)) + ('T' if amt < 0 else 'S')
+    return f'\033[{abs(amt)}{"T" if amt < 0 else "S"}'
 
 
 STANDARD_COLORS = {'black': 0, 'red': 1, 'green': 2, 'yellow': 3, 'blue': 4, 'magenta': 5, 'cyan': 6, 'gray': 7, 'white': 7}
@@ -465,7 +465,7 @@ def as_type_stub() -> str:
     for name, func in all_cmds.items():
         args = ', '.join(func_sig(func))
         if args:
-            args = ', ' + args
+            args = f', {args}'
         methods.append(f'    def {name}(self{args}) -> str: pass')
     ans += ['', '', 'class CMD:'] + methods
 
diff --git a/kittens/unicode_input/main.py b/kittens/unicode_input/main.py
index 0f2e90688..d7c996ca5 100644
--- a/kittens/unicode_input/main.py
+++ b/kittens/unicode_input/main.py
@@ -192,7 +192,7 @@ class Table:
                 if w < 2:
                     text += ' ' * (2 - w)
                 if len(desc) > space_for_desc:
-                    text += desc[:space_for_desc - 1] + '…'
+                    text += f'{desc[:space_for_desc - 1]}…'
                 else:
                     text += desc
                 extra = space_for_desc - len(desc)
diff --git a/kitty/child.py b/kitty/child.py
index 1bca54b7f..a8b990fc9 100644
--- a/kitty/child.py
+++ b/kitty/child.py
@@ -62,7 +62,7 @@ else:
             except Exception:
                 continue
             try:
-                with open('/proc/' + x + '/stat', 'rb') as f:
+                with open(f'/proc/{x}/stat', 'rb') as f:
                     raw = f.read().decode('utf-8')
             except OSError:
                 continue
@@ -268,7 +268,7 @@ class Child:
             # https://github.com/kovidgoyal/kitty/issues/1870
             # xterm, urxvt, konsole and gnome-terminal do not do it in my
             # testing.
-            argv[0] = ('-' + exe.split('/')[-1])
+            argv[0] = (f'-{exe.split("/")[-1]}')
         exe = which(exe) or exe
         pid = fast_data_types.spawn(exe, self.cwd, tuple(argv), env, master, slave, stdin_read_fd, stdin_write_fd, ready_read_fd, ready_write_fd)
         os.close(slave)
diff --git a/kitty/cli_stub.py b/kitty/cli_stub.py
index c14f83549..53714af3d 100644
--- a/kitty/cli_stub.py
+++ b/kitty/cli_stub.py
@@ -82,7 +82,7 @@ def generate_stub() -> None:
     for cmd_name in all_command_names():
         cmd = command_for_name(cmd_name)
         if cmd.options_spec:
-            do(cmd.options_spec, cmd.__class__.__name__ + 'RCOptions')
+            do(cmd.options_spec, f'{cmd.__class__.__name__}RCOptions')
 
     save_type_stub(text, __file__)
 
diff --git a/kitty/client.py b/kitty/client.py
index ab727b681..3417f4ad5 100644
--- a/kitty/client.py
+++ b/kitty/client.py
@@ -12,8 +12,8 @@ from contextlib import suppress
 from typing import Any
 
 
-CSI = '\033['
-OSC = '\033]'
+CSI = '\x1b['
+OSC = '\x1b]'
 
 
 def write(x: str) -> None:
@@ -42,11 +42,11 @@ def screen_alternate_keypad_mode() -> None:
 
 
 def screen_cursor_position(y: int, x: int) -> None:
-    write(CSI + f'{y};{x}H')
+    write(f'{CSI}{y};{x}H')
 
 
 def screen_cursor_forward(amt: int) -> None:
-    write(CSI + '%sC' % amt)
+    write(f'{CSI}{amt}C')
 
 
 def screen_save_cursor() -> None:
@@ -58,105 +58,105 @@ def screen_restore_cursor() -> None:
 
 
 def screen_cursor_back1(amt: int) -> None:
-    write(CSI + '%sD' % amt)
+    write(f'{CSI}{amt}D')
 
 
 def screen_save_modes() -> None:
-    write(CSI + '?s')
+    write(f'{CSI}?s')
 
 
 def screen_restore_modes() -> None:
-    write(CSI + '?r')
+    write(f'{CSI}?r')
 
 
 def screen_designate_charset(which: int, to: int) -> None:
     w = '()'[int(which)]
     t = chr(int(to))
-    write('\033' + w + t)
+    write(f'\x1b{w}{t}')
 
 
 def select_graphic_rendition(*a: int) -> None:
-    write(CSI + '%sm' % ';'.join(map(str, a)))
+    write(f'{CSI}{";".join(map(str, a))}m')
 
 
 def screen_cursor_to_column(c: int) -> None:
-    write(CSI + '%dG' % c)
+    write(f'{CSI}{c}G')
 
 
 def screen_cursor_to_line(ln: int) -> None:
-    write(CSI + '%dd' % ln)
+    write(f'{CSI}{ln}d')
 
 
 def screen_set_mode(x: int, private: bool) -> None:
-    write(CSI + ('?' if private else '') + str(x) + 'h')
+    write(f'{CSI}{"?" if private else ""}{x}h')
 
 
 def screen_save_mode(x: int, private: bool) -> None:
-    write(CSI + ('?' if private else '') + str(x) + 's')
+    write(f'{CSI}{"?" if private else ""}{x}s')
 
 
 def screen_reset_mode(x: int, private: bool) -> None:
-    write(CSI + ('?' if private else '') + str(x) + 'l')
+    write(f'{CSI}{"?" if private else ""}{x}l')
 
 
 def screen_restore_mode(x: int, private: bool) -> None:
-    write(CSI + ('?' if private else '') + str(x) + 'r')
+    write(f'{CSI}{"?" if private else ""}{x}r')
 
 
 def screen_set_margins(t: int, b: int) -> None:
-    write(CSI + '%d;%dr' % (t, b))
+    write(f'{CSI}{t};{b}r')
 
 
 def screen_indexn(n: int) -> None:
-    write(CSI + '%dS' % n)
+    write(f'{CSI}{n}S')
 
 
 def screen_delete_characters(count: int) -> None:
-    write(CSI + '%dP' % count)
+    write(f'{CSI}{count}P')
 
 
 def screen_push_colors(which: int) -> None:
-    write(CSI + '%d#P' % which)
+    write(f'{CSI}{which}#P')
 
 
 def screen_pop_colors(which: int) -> None:
-    write(CSI + '%d#Q' % which)
+    write(f'{CSI}{which}#Q')
 
 
 def screen_report_colors() -> None:
-    write(CSI + '#R')
+    write(f'{CSI}#R')
 
 
 def screen_repeat_character(num: int) -> None:
-    write(CSI + '%db' % num)
+    write(f'{CSI}{num}b')
 
 
 def screen_insert_characters(count: int) -> None:
-    write(CSI + '%d@' % count)
+    write(f'{CSI}{count}@')
 
 
 def screen_scroll(count: int) -> None:
-    write(CSI + '%dS' % count)
+    write(f'{CSI}{count}S')
 
 
 def screen_erase_in_display(how: int, private: bool) -> None:
-    write(CSI + ('?' if private else '') + str(how) + 'J')
+    write(f'{CSI}{"?" if private else ""}{how}J')
 
 
 def screen_erase_in_line(how: int, private: bool) -> None:
-    write(CSI + ('?' if private else '') + str(how) + 'K')
+    write(f'{CSI}{"?" if private else ""}{how}K')
 
 
 def screen_delete_lines(num: int) -> None:
-    write(CSI + str(num) + 'M')
+    write(f'{CSI}{num}M')
 
 
 def screen_cursor_up2(count: int) -> None:
-    write(CSI + '%dA' % count)
+    write(f'{CSI}{count}A')
 
 
 def screen_cursor_down(count: int) -> None:
-    write(CSI + '%dB' % count)
+    write(f'{CSI}{count}B')
 
 
 def screen_carriage_return() -> None:
@@ -176,11 +176,11 @@ def screen_backspace() -> None:
 
 
 def screen_set_cursor(mode: int, secondary: int) -> None:
-    write(CSI + '%d q' % secondary)
+    write(f'{CSI}{secondary} q')
 
 
 def screen_insert_lines(num: int) -> None:
-    write(CSI + '%dL' % num)
+    write(f'{CSI}{num}L')
 
 
 def draw(*a: str) -> None:
@@ -188,7 +188,7 @@ def draw(*a: str) -> None:
 
 
 def screen_manipulate_title_stack(op: int, which: int) -> None:
-    write(CSI + '%d;%dt' % (op, which))
+    write(f'{CSI}{op};{which}t')
 
 
 def report_device_attributes(mode: int, char: int) -> None:
@@ -197,21 +197,22 @@ def report_device_attributes(mode: int, char: int) -> None:
         x += chr(char)
     if mode:
         x += str(mode)
-    write(CSI + x + 'c')
+    write(f'{CSI}{x}c')
 
 
 def screen_decsace(mode: int) -> None:
-    write(CSI + str(mode) + '*x')
+    write(f'{CSI}{mode}*x')
 
 
 def screen_set_8bit_controls(mode: int) -> None:
-    write('\x1b ' + ('G' if mode else 'F'))
+    write(f'\x1b {"G" if mode else "F"}')
 
 
 def write_osc(code: int, string: str = '') -> None:
     if string:
-        string = ';' + string
-    write(OSC + str(code) + string + '\x07')
+        write(f'{OSC}{code};{string}\x07')
+    else:
+        write(f'{OSC}{code}\x07')
 
 
 set_dynamic_color = set_color_table_color = process_cwd_notification = write_osc
@@ -235,7 +236,7 @@ def clipboard_control(payload: str) -> None:
         clipboard_control_pending += data.lstrip(';')
         payload = clipboard_control_pending
         clipboard_control_pending = ''
-    write(OSC + payload + '\x07')
+    write(f'{OSC}{payload}\x07')
 
 
 def replay(raw: str) -> None:
diff --git a/kitty/complete.py b/kitty/complete.py
index dcaf14841..d3a49f978 100644
--- a/kitty/complete.py
+++ b/kitty/complete.py
@@ -270,7 +270,7 @@ def zsh_output_serializer(ans: Completions) -> str:
         yield ans
 
     for description, matches in ans.match_groups.items():
-        cmd = ['compadd', '-U', '-J', shlex.quote(description), '-X', shlex.quote('%B' + description + '%b')]
+        cmd = ['compadd', '-U', '-J', shlex.quote(description), '-X', shlex.quote(f'%B{description}%b')]
         if not matches.trailing_space:
             cmd += ['-S', '""']
         if matches.is_files:
@@ -350,10 +350,10 @@ def fish2_output_serializer(ans: Completions) -> str:
 
 
 def completions_for_first_word(ans: Completions, prefix: str, entry_points: Iterable[str], namespaced_entry_points: Iterable[str]) -> None:
-    cmds = ['@' + c for c in remote_control_command_names()]
+    cmds = [f'@{c}' for c in remote_control_command_names()]
     ans.add_match_group('Entry points', {
         k: '' for k in
-        list(entry_points) + cmds + ['+' + k for k in namespaced_entry_points]
+        list(entry_points) + cmds + [f'+{k}' for k in namespaced_entry_points]
         if not prefix or k.startswith(prefix)
     })
     if prefix:
@@ -443,7 +443,7 @@ def complete_alias_map(
                 long_opt = option_map.get(parts[0])
                 if long_opt is not None and complete_args is not None:
                     complete_args(ans, long_opt, parts[1], Delegate())
-                    ans.add_prefix(parts[0] + '=')
+                    ans.add_prefix(f'{parts[0]}=')
                 return
         opt = option_map.get(w)
         if w is last_word and not new_word:
@@ -682,7 +682,7 @@ def find_completions(words: Sequence[str], new_word: bool, entry_points: Iterabl
     if words[0].startswith('@'):
         if len(words) == 1 and not new_word:
             prefix = words[0]
-            ans.add_match_group('Remote control commands', {'@' + c: '' for c in remote_control_command_names() if c.startswith(prefix)})
+            ans.add_match_group('Remote control commands', {f'@{c}': '' for c in remote_control_command_names() if c.startswith(prefix)})
         else:
             complete_remote_command(ans, words[0][1:], words[1:], new_word)
     if words[0] == '+':
diff --git a/kitty/conf/generate.py b/kitty/conf/generate.py
index e8edc2b19..a1c0166a9 100644
--- a/kitty/conf/generate.py
+++ b/kitty/conf/generate.py
@@ -418,9 +418,9 @@ def generate_c_conversion(loc: str, ctypes: List[Option]) -> str:
 def write_output(loc: str, defn: Definition) -> None:
     cls, tc = generate_class(defn, loc)
     with open(os.path.join(*loc.split('.'), 'options', 'types.py'), 'w') as f:
-        f.write(cls + '\n')
+        f.write(f'{cls}\n')
     with open(os.path.join(*loc.split('.'), 'options', 'parse.py'), 'w') as f:
-        f.write(tc + '\n')
+        f.write(f'{tc}\n')
     ctypes = []
     for opt in defn.root_group.iter_all_non_groups():
         if isinstance(opt, Option) and opt.ctype:
@@ -428,7 +428,7 @@ def write_output(loc: str, defn: Definition) -> None:
     if ctypes:
         c = generate_c_conversion(loc, ctypes)
         with open(os.path.join(*loc.split('.'), 'options', 'to-c-generated.h'), 'w') as f:
-            f.write(c + '\n')
+            f.write(f'{c}\n')
 
 
 def main() -> None:
@@ -454,6 +454,6 @@ def main() -> None:
     loc = package_name
     cls, tc = generate_class(defn, loc)
     with open(os.path.join(os.path.dirname(path), 'kitten_options_types.py'), 'w') as f:
-        f.write(cls + '\n')
+        f.write(f'{cls}\n')
     with open(os.path.join(os.path.dirname(path), 'kitten_options_parse.py'), 'w') as f:
-        f.write(tc + '\n')
+        f.write(f'{tc}\n')
diff --git a/kitty/conf/types.py b/kitty/conf/types.py
index 03ab3df19..774d666b3 100644
--- a/kitty/conf/types.py
+++ b/kitty/conf/types.py
@@ -37,8 +37,8 @@ def expand_opt_references(conf_name: str, text: str) -> str:
     def expand(m: 'Match[str]') -> str:
         ref = m.group(1)
         if '<' not in ref and '.' not in ref:
-            full_ref = conf_name + ref
-            return f':opt:`{ref} <{full_ref}>`'
+            # full ref
+            return f':opt:`{ref} <{conf_name}{ref}>`'
         return str(m.group())
 
     return re.sub(r':opt:`(.+?)`', expand, text)
@@ -214,7 +214,7 @@ class Option:
         if not self.documented:
             return ans
         mopts = [self] + option_group
-        a('.. opt:: ' + ', '.join(conf_name + '.' + mo.name for mo in mopts))
+        a('.. opt:: ' + ', '.join(f'{conf_name}.{mo.name}' for mo in mopts))
         a('.. code-block:: conf')
         a('')
         sz = max(len(x.name) for x in mopts)
@@ -330,7 +330,7 @@ class Mapping:
             raise ValueError(f'The shortcut for {self.name} has no short_text')
         sc_text = f'{conf_name}.{self.short_text}'
         shortcut_slugs[f'{conf_name}.{self.name}'] = (sc_text, self.key_text.replace('kitty_mod', kitty_mod))
-        a('.. shortcut:: ' + sc_text)
+        a(f'.. shortcut:: {sc_text}')
         block_started = False
         for sc in [self] + action_group:
             if sc.add_to_default and sc.documented:
@@ -534,7 +534,7 @@ class Group:
                     ans[i] = ' '.join(parts)
 
             if commented:
-                ans = [x if x.startswith('#') or not x.strip() else ('# ' + x) for x in ans]
+                ans = [x if x.startswith('#') or not x.strip() else (f'# {x}') for x in ans]
 
         return ans
 
diff --git a/kitty/config.py b/kitty/config.py
index 1df21c944..745e1c07d 100644
--- a/kitty/config.py
+++ b/kitty/config.py
@@ -54,7 +54,7 @@ def atomic_save(data: bytes, path: str) -> None:
 
 @contextmanager
 def cached_values_for(name: str) -> Generator[Dict[str, Any], None, None]:
-    cached_path = os.path.join(cache_dir(), name + '.json')
+    cached_path = os.path.join(cache_dir(), f'{name}.json')
     cached_values: Dict[str, Any] = {}
     try:
         with open(cached_path, 'rb') as f:
diff --git a/kitty/fonts/core_text.py b/kitty/fonts/core_text.py
index 6718fc0f2..b9e4735b4 100644
--- a/kitty/fonts/core_text.py
+++ b/kitty/fonts/core_text.py
@@ -29,7 +29,7 @@ def create_font_map(all_fonts: Iterable[CoreTextFont]) -> FontMap:
         ps = (x['postscript_name'] or '').lower()
         ans['family_map'].setdefault(f, []).append(x)
         ans['ps_map'].setdefault(ps, []).append(x)
-        ans['full_map'].setdefault(f + ' ' + s, []).append(x)
+        ans['full_map'].setdefault(f'{f} {s}', []).append(x)
     return ans
 
 
@@ -45,7 +45,7 @@ def list_fonts() -> Generator[ListedFont, None, None]:
     for fd in coretext_all_fonts():
         f = fd['family']
         if f:
-            fn = (f + ' ' + (fd['style'] or '')).strip()
+            fn = f'{f} {fd.get("style", "")}'.strip()
             is_mono = bool(fd['monospace'])
             yield {'family': f, 'full_name': fn, 'postscript_name': fd['postscript_name'] or '', 'is_monospace': is_mono}
 
diff --git a/kitty/fonts/fontconfig.py b/kitty/fonts/fontconfig.py
index 763f8d333..01c3ba047 100644
--- a/kitty/fonts/fontconfig.py
+++ b/kitty/fonts/fontconfig.py
@@ -58,7 +58,7 @@ def list_fonts() -> Generator[ListedFont, None, None]:
             if fn_:
                 fn = str(fn_)
             else:
-                fn = (f + ' ' + str(fd.get('style', ''))).strip()
+                fn = f'{f} {fd.get("style", "")}'.strip()
             is_mono = fd.get('spacing') in ('MONO', 'DUAL')
             yield {'family': f, 'full_name': fn, 'postscript_name': str(fd.get('postscript_name', '')), 'is_monospace': is_mono}
 
diff --git a/kitty/fonts/list.py b/kitty/fonts/list.py
index 7cbc65209..e56343823 100644
--- a/kitty/fonts/list.py
+++ b/kitty/fonts/list.py
@@ -28,13 +28,13 @@ def main(argv: Sequence[str]) -> None:
     groups = create_family_groups()
     for k in sorted(groups, key=lambda x: x.lower()):
         if isatty:
-            print('\033[1;32m' + k + '\033[m')
+            print(f'\033[1;32m{k}\033[m')
         else:
             print(k)
         for f in sorted(groups[k], key=lambda x: x['full_name'].lower()):
             p = f['full_name']
             if isatty:
-                p = '\033[3m' + p + '\033[m'
+                p = f'\033[3m{p}\033[m'
             if psnames:
                 p += ' ({})'.format(f['postscript_name'])
             print('   ', p)
diff --git a/kitty/fonts/render.py b/kitty/fonts/render.py
index 500acb950..e617897a2 100644
--- a/kitty/fonts/render.py
+++ b/kitty/fonts/render.py
@@ -515,7 +515,7 @@ def test_fallback_font(qtext: Optional[str] = None, bold: bool = False, italic:
             try:
                 print(text, f)
             except UnicodeEncodeError:
-                sys.stdout.buffer.write((text + ' %s\n' % f).encode('utf-8'))
+                sys.stdout.buffer.write(f'{text} {f}\n'.encode('utf-8'))
 
 
 def showcase() -> None:
diff --git a/kitty/guess_mime_type.py b/kitty/guess_mime_type.py
index cc03e8b6c..e392cacf8 100644
--- a/kitty/guess_mime_type.py
+++ b/kitty/guess_mime_type.py
@@ -58,7 +58,7 @@ def guess_type(path: str, allow_filesystem_access: bool = False) -> Optional[str
         ext = path.rpartition('.')[-1].lower()
         mt = known_extensions.get(ext)
     if mt in text_mimes:
-        mt = 'text/' + mt.split('/', 1)[-1]
+        mt = f'text/{mt.split("/", 1)[-1]}'
     if not mt and is_rc_file(path):
         mt = 'text/plain'
     if not mt and is_folder(path):
diff --git a/kitty/key_encoding.c b/kitty/key_encoding.c
index b0a7825e6..b132905e8 100644
--- a/kitty/key_encoding.c
+++ b/kitty/key_encoding.c
@@ -219,7 +219,6 @@ encode_function_key(const KeyEvent *ev, char *output) {
         case GLFW_FKEY_PAGE_UP: S(5, '~');
         case GLFW_FKEY_PAGE_DOWN: S(6, '~');
         case GLFW_FKEY_HOME: S(1, 'H');
-        case GLFW_FKEY_KP_BEGIN: S(1, 'E');
         case GLFW_FKEY_END: S(1, 'F');
         case GLFW_FKEY_F1: S(1, 'P');
         case GLFW_FKEY_F2: S(1, 'Q');
@@ -233,6 +232,7 @@ encode_function_key(const KeyEvent *ev, char *output) {
         case GLFW_FKEY_F10: S(21, '~');
         case GLFW_FKEY_F11: S(23, '~');
         case GLFW_FKEY_F12: S(24, '~');
+        case GLFW_FKEY_KP_BEGIN: S(1, 'E');
 /* end special numbers */
         case GLFW_FKEY_MENU:
             // use the same encoding as xterm for this key in legacy mode (F16)
diff --git a/kitty/key_encoding.py b/kitty/key_encoding.py
index 02f1d38c7..49ab1ad58 100644
--- a/kitty/key_encoding.py
+++ b/kitty/key_encoding.py
@@ -181,7 +181,7 @@ class EventType(IntEnum):
 @lru_cache(maxsize=128)
 def parse_shortcut(spec: str) -> ParsedShortcut:
     if spec.endswith('+'):
-        spec = spec[:-1] + 'plus'
+        spec = f'{spec[:-1]}plus'
     parts = spec.split('+')
     key_name = parts[-1]
     key_name = functional_key_name_aliases.get(key_name.upper(), key_name)
diff --git a/kitty/key_names.py b/kitty/key_names.py
index 35e639193..edda8b252 100644
--- a/kitty/key_names.py
+++ b/kitty/key_names.py
@@ -63,7 +63,7 @@ else:
         import ctypes
         for suffix in ('.0', ''):
             with suppress(Exception):
-                lib = ctypes.CDLL('libxkbcommon.so' + suffix)
+                lib = ctypes.CDLL(f'libxkbcommon.so{suffix}')
                 break
         else:
             from ctypes.util import find_library
diff --git a/kitty/launch.py b/kitty/launch.py
index 33365025b..f8b4ee932 100644
--- a/kitty/launch.py
+++ b/kitty/launch.py
@@ -369,7 +369,7 @@ def launch(
         if opts.stdin_add_formatting:
             if q in ('@screen', '@screen_scrollback', '@alternate', '@alternate_scrollback',
                      '@first_cmd_output_on_screen', '@last_cmd_output', '@last_visited_cmd_output'):
-                q = '@ansi_' + q[1:]
+                q = f'@ansi_{q[1:]}'
         if opts.stdin_add_line_wrap_markers:
             q += '_wrap'
         penv, stdin = boss.process_stdin_source(window=active, stdin=q, copy_pipe_data=pipe_data)
diff --git a/kitty/layout/base.py b/kitty/layout/base.py
index 1843c6ae2..9310248bb 100644
--- a/kitty/layout/base.py
+++ b/kitty/layout/base.py
@@ -217,7 +217,7 @@ class Layout:
         self.blank_rects: List[Rect] = []
         self.layout_opts = self.parse_layout_opts(layout_opts)
         assert self.name is not None
-        self.full_name = self.name + ((':' + layout_opts) if layout_opts else '')
+        self.full_name = f'{self.name}:{layout_opts}' if layout_opts else self.name
         self.remove_all_biases()
 
     def bias_increment_for_cell(self, is_horizontal: bool) -> float:
diff --git a/kitty/main.py b/kitty/main.py
index 458bb455e..6a1ba10fa 100644
--- a/kitty/main.py
+++ b/kitty/main.py
@@ -44,7 +44,7 @@ def set_custom_ibeam_cursor() -> None:
         data = f.read()
     rgba_data, width, height = load_png_data(data)
     c2x = os.path.splitext(beam_cursor_data_file)
-    with open(c2x[0] + '@2x' + c2x[1], 'rb') as f:
+    with open(f'{c2x[0]}@2x{c2x[1]}', 'rb') as f:
         data = f.read()
     rgba_data2, width2, height2 = load_png_data(data)
     images = (rgba_data, width, height), (rgba_data2, width2, height2)
@@ -138,7 +138,7 @@ def get_macos_shortcut_for(
 def set_x11_window_icon() -> None:
     # max icon size on X11 64bits is 128x128
     path, ext = os.path.splitext(logo_png_file)
-    set_default_window_icon(path + '-128' + ext)
+    set_default_window_icon(f'{path}-128{ext}')
 
 
 def _run_app(opts: Options, args: CLIOptions, bad_lines: Sequence[BadLine] = ()) -> None:
@@ -220,7 +220,7 @@ def ensure_macos_locale() -> None:
                     lang = 'en_US'
                 else:
                     log_error(f'Could not set LANG Cocoa returns language as: {lang}')
-            os.environ['LANG'] = lang + '.UTF-8'
+            os.environ['LANG'] = f'{lang}.UTF-8'
 
 
 @contextmanager
diff --git a/kitty/notify.py b/kitty/notify.py
index 2ed16bae4..00dfff5a6 100644
--- a/kitty/notify.py
+++ b/kitty/notify.py
@@ -113,7 +113,7 @@ def parse_osc_99(raw: str) -> NotificationCommand:
             elif k == 'd':
                 cmd.done = v != '0'
             elif k == 'a':
-                cmd.actions += ',' + v
+                cmd.actions += f',{v}'
     if payload_type not in ('body', 'title'):
         log_error(f'Malformed OSC 99: unknown payload type: {payload_type}')
         return NotificationCommand()
@@ -139,7 +139,7 @@ def limit_size(x: str) -> str:
 def merge_osc_99(prev: NotificationCommand, cmd: NotificationCommand) -> NotificationCommand:
     if prev.done or prev.identifier != cmd.identifier:
         return cmd
-    cmd.actions = limit_size(prev.actions + ',' + cmd.actions)
+    cmd.actions = limit_size(f'{prev.actions},{cmd.actions}')
     cmd.title = limit_size(prev.title + cmd.title)
     cmd.body = limit_size(prev.body + cmd.body)
     return cmd
@@ -198,7 +198,7 @@ def notify_with_command(cmd: NotificationCommand, window_id: int, notify_impleme
     title = cmd.title or cmd.body
     body = cmd.body if cmd.title else ''
     if title:
-        identifier = 'i' + str(next(id_counter))
+        identifier = f'i{next(id_counter)}'
         notify_implementation(title, body, identifier)
         register_identifier(identifier, cmd, window_id)
 
diff --git a/kitty/open_actions.py b/kitty/open_actions.py
index b4bf34698..5009b81da 100644
--- a/kitty/open_actions.py
+++ b/kitty/open_actions.py
@@ -114,7 +114,7 @@ def url_matches_criterion(purl: 'ParseResult', url: str, unquoted_path: str, mc:
         path = unquoted_path.lower()
         for ext in mc.value.split(','):
             ext = ext.strip()
-            if path.endswith('.' + ext):
+            if path.endswith(f'.{ext}'):
                 return True
         return False
 
diff --git a/kitty/options/utils.py b/kitty/options/utils.py
index 1a735b62d..1e90097a7 100644
--- a/kitty/options/utils.py
+++ b/kitty/options/utils.py
@@ -379,7 +379,7 @@ def parse_mods(parts: Iterable[str], sc: str) -> Optional[int]:
     mods = 0
     for m in parts:
         try:
-            mods |= getattr(defines, 'GLFW_MOD_' + map_mod(m.upper()))
+            mods |= getattr(defines, f'GLFW_MOD_{map_mod(m.upper())}')
         except AttributeError:
             if m.upper() != 'NONE':
                 log_error(f'Shortcut: {sc} has unknown modifier, ignoring')
@@ -394,7 +394,7 @@ def to_modifiers(val: str) -> int:
 
 def parse_shortcut(sc: str) -> SingleKey:
     if sc.endswith('+') and len(sc) > 1:
-        sc = sc[:-1] + 'plus'
+        sc = f'{sc[:-1]}plus'
     parts = sc.split('+')
     mods = 0
     if len(parts) > 1:
@@ -895,13 +895,13 @@ def resolve_aliases_and_parse_actions(
             parts = rest.split(maxsplit=1)
             if parts[0] != alias.name:
                 continue
-            new_defn = possible_alias + ' ' + alias.value + ((' ' + parts[1]) if len(parts) > 1 else '')
+            new_defn = f'{possible_alias} {alias.value} {f" {parts[1]}" if len(parts) > 1 else ""}'
             new_aliases = aliases.copy()
             new_aliases[possible_alias] = [a for a in aliases[possible_alias] if a is not alias]
             yield from resolve_aliases_and_parse_actions(new_defn, new_aliases, map_type)
             return
         else:  # action_alias
-            new_defn = alias.value + ((' ' + rest) if rest else '')
+            new_defn = f'{alias.value} {rest}' if rest else alias.value
             new_aliases = aliases.copy()
             new_aliases.pop(possible_alias)
             yield from resolve_aliases_and_parse_actions(new_defn, new_aliases, map_type)
@@ -909,7 +909,7 @@ def resolve_aliases_and_parse_actions(
 
     if possible_alias == 'combine':
         sep, rest = rest.split(maxsplit=1)
-        parts = re.split(r'\s*' + re.escape(sep) + r'\s*', rest)
+        parts = re.split(fr'\s*{re.escape(sep)}\s*', rest)
         for x in parts:
             if x:
                 yield from resolve_aliases_and_parse_actions(x, aliases, map_type)
diff --git a/kitty/parse-graphics-command.h b/kitty/parse-graphics-command.h
index e602d676f..025055ea8 100644
--- a/kitty/parse-graphics-command.h
+++ b/kitty/parse-graphics-command.h
@@ -1,5 +1,4 @@
-// This file is generated by /home/kovid/work/kitty/./gen-apc-parsers.py do not
-// edit!
+// This file is generated by gen-apc-parsers.py do not edit!
 
 #pragma once
 
@@ -148,9 +147,9 @@ static inline void parse_graphics_code(Screen *screen,
 
       case action: {
         g.action = screen->parser_buf[pos++] & 0xff;
-        if (g.action != 'q' && g.action != 'p' && g.action != 't' &&
-            g.action != 'd' && g.action != 'c' && g.action != 'a' &&
-            g.action != 'T' && g.action != 'f') {
+        if (g.action != 'T' && g.action != 'a' && g.action != 'c' &&
+            g.action != 'd' && g.action != 'f' && g.action != 'p' &&
+            g.action != 'q' && g.action != 't') {
           REPORT_ERROR("Malformed GraphicsCommand control block, unknown flag "
                        "value for action: 0x%x",
                        g.action);
@@ -160,16 +159,16 @@ static inline void parse_graphics_code(Screen *screen,
 
       case delete_action: {
         g.delete_action = screen->parser_buf[pos++] & 0xff;
-        if (g.delete_action != 'q' && g.delete_action != 'Q' &&
-            g.delete_action != 'c' && g.delete_action != 'C' &&
-            g.delete_action != 'N' && g.delete_action != 'i' &&
-            g.delete_action != 'A' && g.delete_action != 'y' &&
-            g.delete_action != 'a' && g.delete_action != 'I' &&
-            g.delete_action != 'F' && g.delete_action != 'p' &&
-            g.delete_action != 'z' && g.delete_action != 'x' &&
-            g.delete_action != 'n' && g.delete_action != 'X' &&
-            g.delete_action != 'Y' && g.delete_action != 'P' &&
-            g.delete_action != 'Z' && g.delete_action != 'f') {
+        if (g.delete_action != 'A' && g.delete_action != 'C' &&
+            g.delete_action != 'F' && g.delete_action != 'I' &&
+            g.delete_action != 'N' && g.delete_action != 'P' &&
+            g.delete_action != 'Q' && g.delete_action != 'X' &&
+            g.delete_action != 'Y' && g.delete_action != 'Z' &&
+            g.delete_action != 'a' && g.delete_action != 'c' &&
+            g.delete_action != 'f' && g.delete_action != 'i' &&
+            g.delete_action != 'n' && g.delete_action != 'p' &&
+            g.delete_action != 'q' && g.delete_action != 'x' &&
+            g.delete_action != 'y' && g.delete_action != 'z') {
           REPORT_ERROR("Malformed GraphicsCommand control block, unknown flag "
                        "value for delete_action: 0x%x",
                        g.delete_action);
@@ -179,8 +178,8 @@ static inline void parse_graphics_code(Screen *screen,
 
       case transmission_type: {
         g.transmission_type = screen->parser_buf[pos++] & 0xff;
-        if (g.transmission_type != 's' && g.transmission_type != 't' &&
-            g.transmission_type != 'd' && g.transmission_type != 'f') {
+        if (g.transmission_type != 'd' && g.transmission_type != 'f' &&
+            g.transmission_type != 's' && g.transmission_type != 't') {
           REPORT_ERROR("Malformed GraphicsCommand control block, unknown flag "
                        "value for transmission_type: 0x%x",
                        g.transmission_type);
diff --git a/kitty/rc/send_text.py b/kitty/rc/send_text.py
index 1a658029c..8c623c197 100644
--- a/kitty/rc/send_text.py
+++ b/kitty/rc/send_text.py
@@ -107,20 +107,20 @@ Do not send text to the active window, even if it is one of the matched windows.
                         if '\x04' in decoded_data:
                             decoded_data = decoded_data[:decoded_data.index('\x04')]
                             keep_going = False
-                        ret['data'] = 'text:' + decoded_data
+                        ret['data'] = f'text:{decoded_data}'
                         yield ret
             else:
                 while True:
                     data = sys.stdin.buffer.read(limit)
                     if not data:
                         break
-                    ret['data'] = 'base64:' + base64.standard_b64encode(data).decode('ascii')
+                    ret['data'] = f'base64:{base64.standard_b64encode(data).decode("ascii")}'
                     yield ret
 
         def chunks(text: str) -> CmdGenerator:
             data = parse_send_text_bytes(text).decode('utf-8')
             while data:
-                ret['data'] = 'text:' + data[:limit]
+                ret['data'] = f'text:{data[:limit]}'
                 yield ret
                 data = data[limit:]
 
@@ -130,7 +130,7 @@ Do not send text to the active window, even if it is one of the matched windows.
                     data = f.read(limit)
                     if not data:
                         break
-                    ret['data'] = 'base64:' + base64.standard_b64encode(data).decode('ascii')
+                    ret['data'] = f'base64:{base64.standard_b64encode(data).decode("ascii")}'
                     yield ret
 
         sources = []
diff --git a/kitty/rgb.py b/kitty/rgb.py
index ff0e9b3e6..3f81c1950 100644
--- a/kitty/rgb.py
+++ b/kitty/rgb.py
@@ -28,7 +28,7 @@ def parse_single_color(c: str) -> int:
 def parse_sharp(spec: str) -> Optional[Color]:
     if len(spec) in (3, 6, 9, 12):
         part_len = len(spec) // 3
-        colors = re.findall(r'[a-fA-F0-9]{%d}' % part_len, spec)
+        colors = re.findall(fr'[a-fA-F0-9]{{{part_len}}}', spec)
         return Color(*map(parse_single_color, colors))
     return None
 
diff --git a/kitty/shell.py b/kitty/shell.py
index 639837647..6bbedd732 100644
--- a/kitty/shell.py
+++ b/kitty/shell.py
@@ -221,7 +221,7 @@ def real_main(global_opts: RCOptions) -> None:
             if e.code != 0:
                 print(end=output_prefix, flush=True)
                 print_err(e)
-                print_err('Use "{}" to see how to use this command.'.format(emph('help ' + cmd)))
+                print_err('Use "{}" to see how to use this command.'.format(emph(f'help {cmd}')))
             continue
         except Exception:
             print(end=output_prefix, flush=True)
diff --git a/kitty/tab_bar.py b/kitty/tab_bar.py
index 686a4356f..327dc3bcd 100644
--- a/kitty/tab_bar.py
+++ b/kitty/tab_bar.py
@@ -102,14 +102,14 @@ class ColorFormatter:
             ans = '9'
         elif q == 'tab':
             col = color_from_int((self.draw_data.tab_bg if self.which == '4' else self.draw_data.tab_fg)(self.tab_data))
-            ans = '8' + color_as_sgr(col)
+            ans = f'8{color_as_sgr(col)}'
         else:
             if name.startswith('_'):
-                q = '#' + name[1:]
+                q = f'#{name[1:]}'
             c = to_color(q)
             if c is None:
                 raise AttributeError(f'{name} is not a valid color')
-            ans = '8' + color_as_sgr(c)
+            ans = f'8{color_as_sgr(c)}'
         return f'\x1b[{self.which}{ans}m'
 
 
diff --git a/kitty/terminfo.py b/kitty/terminfo.py
index c487a8524..f14744928 100644
--- a/kitty/terminfo.py
+++ b/kitty/terminfo.py
@@ -471,8 +471,8 @@ def get_capabilities(query_string: str, opts: 'Options') -> Generator[str, None,
 
     def result(encoded_query_name: str, x: Optional[str] = None) -> str:
         if x is None:
-            return '0+r' + encoded_query_name
-        return '1+r' + encoded_query_name + '=' + hexlify(str(x).encode('utf-8')).decode('ascii')
+            return f'0+r{encoded_query_name}'
+        return f'1+r{encoded_query_name}={hexlify(str(x).encode("utf-8")).decode("ascii")}'
 
     for encoded_query_name in query_string.split(';'):
         name = qname = unhexlify(encoded_query_name).decode('utf-8')
diff --git a/publish.py b/publish.py
index 063862c14..08dd3aedb 100755
--- a/publish.py
+++ b/publish.py
@@ -40,7 +40,7 @@ def echo_cmd(cmd: Iterable[str]) -> None:
     isatty = sys.stdout.isatty()
     end = '\n'
     if isatty:
-        end = '\x1b[m' + end
+        end = f'\x1b[m{end}'
         print('\x1b[92m', end='')
     print(shlex.join(cmd), end=end, flush=True)
 
@@ -146,11 +146,11 @@ def run_website(args: Any) -> None:
 
 
 def sign_file(path: str) -> None:
-    dest = path + '.sig'
+    dest = f'{path}.sig'
     with suppress(FileNotFoundError):
         os.remove(dest)
     subprocess.check_call([
-        os.environ['PENV'] + '/gpg-as-kovid', '--output', path + '.sig',
+        os.environ['PENV'] + '/gpg-as-kovid', '--output', f'{path}.sig',
         '--detach-sig', path
     ])
 
@@ -159,7 +159,7 @@ def run_sdist(args: Any) -> None:
     with tempfile.TemporaryDirectory() as tdir:
         base = os.path.join(tdir, f'kitty-{version}')
         os.mkdir(base)
-        subprocess.check_call('git archive HEAD | tar -x -C ' + base, shell=True)
+        subprocess.check_call(f'git archive HEAD | tar -x -C {base}', shell=True)
         dest = os.path.join(base, 'docs', '_build')
         os.mkdir(dest)
         for x in 'html man'.split():
@@ -167,9 +167,9 @@ def run_sdist(args: Any) -> None:
         dest = os.path.abspath(os.path.join('build', f'kitty-{version}.tar'))
         subprocess.check_call(['tar', '-cf', dest, os.path.basename(base)], cwd=tdir)
         with suppress(FileNotFoundError):
-            os.remove(dest + '.xz')
+            os.remove(f'{dest}.xz')
         subprocess.check_call(['xz', '-9', dest])
-        sign_file(dest + '.xz')
+        sign_file(f'{dest}.xz')
 
 
 class ReadFileWithProgressReporting(io.FileIO):  # {{{
@@ -231,7 +231,7 @@ class Base:  # {{{
 
 class GitHub(Base):  # {{{
 
-    API = 'https://api.github.com/'
+    API = 'https://api.github.com'
 
     def __init__(
         self,
@@ -244,12 +244,12 @@ class GitHub(Base):  # {{{
     ):
         self.files, self.reponame, self.version, self.username, self.password, self.replace = (
             files, reponame, version, username, password, replace)
-        self.current_tag_name = self.version if self.version == 'nightly' else ('v' + self.version)
+        self.current_tag_name = self.version if self.version == 'nightly' else f'v{self.version}'
         self.is_nightly = self.current_tag_name == 'nightly'
         self.requests = s = requests.Session()
         s.auth = (self.username, self.password)
         s.headers.update({'Accept': 'application/vnd.github.v3+json'})
-        self.url_base = f'{self.API}repos/{self.username}/{self.reponame}/releases/'
+        self.url_base = f'{self.API}/repos/{self.username}/{self.reponame}/releases'
 
     def patch(self, url: str, fail_msg: str, **data: Any) -> None:
         rdata = json.dumps(data)
@@ -262,7 +262,7 @@ class GitHub(Base):  # {{{
             self.fail(r, fail_msg)
 
     def update_nightly_description(self, release_id: int) -> None:
-        url = self.url_base + str(release_id)
+        url = f'{self.url_base}/{release_id}'
         now = str(datetime.datetime.utcnow()).split('.')[0] + ' UTC'
         with open('.git/refs/heads/master') as f:
             commit = f.read().strip()
@@ -276,7 +276,7 @@ class GitHub(Base):  # {{{
         # self.clean_older_releases(releases)
         release = self.create_release()
         upload_url = release['upload_url'].partition('{')[0]
-        asset_url = self.url_base + 'assets/{}'
+        asset_url = f'{self.url_base}/assets/{{}}'
         existing_assets = self.existing_assets(release['id'])
         if self.is_nightly:
             for fname in existing_assets:
@@ -308,7 +308,7 @@ class GitHub(Base):  # {{{
                 self.info(f'\nDeleting old released installers from: {release["tag_name"]}')
                 for asset in release['assets']:
                     r = self.requests.delete(
-                        f'{self.API}repos/{self.username}/{self.reponame}/releases/assets/{asset["id"]}')
+                        f'{self.url_base}/assets/{asset["id"]}')
                     if r.status_code != 204:
                         self.fail(r, f'Failed to delete obsolete asset: {asset["name"]} for release: {release["tag_name"]}')
 
@@ -336,7 +336,7 @@ class GitHub(Base):  # {{{
         return bool(error_code == 'already_exists')
 
     def existing_assets(self, release_id: str) -> Dict[str, str]:
-        url = f'{self.API}repos/{self.username}/{self.reponame}/releases/{release_id}/assets'
+        url = f'{self.url_base}/{release_id}/assets'
         r = self.requests.get(url)
         if r.status_code != 200:
             self.fail(r, 'Failed to get assets for release')
@@ -345,15 +345,14 @@ class GitHub(Base):  # {{{
     def create_release(self) -> Dict[str, Any]:
         ' Create a release on GitHub or if it already exists, return the existing release '
         # Check for existing release
-        url = f'{self.API}repos/{self.username}/{self.reponame}/releases/tags/{self.current_tag_name}'
+        url = f'{self.url_base}/tags/{self.current_tag_name}'
         r = self.requests.get(url)
         if r.status_code == 200:
             return dict(r.json())
         if self.is_nightly:
             raise SystemExit('No existing nightly release found on GitHub')
-        url = f'{self.API}repos/{self.username}/{self.reponame}/releases'
         r = self.requests.post(
-            url,
+            self.url_base,
             data=json.dumps({
                 'tag_name': self.current_tag_name,
                 'target_commitish': 'master',
@@ -394,7 +393,7 @@ def files_for_upload() -> Dict[str, str]:
     files[f'build/kitty-{version}.tar.xz.sig'] = 'Source code GPG signature'
     for path, desc in signatures.items():
         sign_file(path)
-        files[path + '.sig'] = desc
+        files[f'{path}.sig'] = desc
     for f in files:
         if not os.path.exists(f):
             raise SystemExit(f'The release artifact {f} does not exist')
@@ -460,7 +459,7 @@ def exec_actions(actions: Iterable[str], args: Any) -> None:
     for action in actions:
         print('Running', action)
         cwd = os.getcwd()
-        globals()['run_' + action](args)
+        globals()[f'run_{action}'](args)
         os.chdir(cwd)
 
 
diff --git a/setup.py b/setup.py
index e5678aec6..c79b7985f 100755
--- a/setup.py
+++ b/setup.py
@@ -710,7 +710,7 @@ def compile_c_extension(
     def on_success() -> None:
         os.rename(dest, real_dest)
 
-    compilation_database.add_command(desc, cmd, partial(newer, real_dest, *objects), on_success=on_success, key=CompileKey('', module + '.so'))
+    compilation_database.add_command(desc, cmd, partial(newer, real_dest, *objects), on_success=on_success, key=CompileKey('', f'{module}.so'))
 
 
 def find_c_files() -> Tuple[List[str], List[str]]:
@@ -1112,7 +1112,7 @@ def create_macos_app_icon(where: str = 'Resources') -> None:
             'iconutil', '-c', 'icns', iconset_dir, '-o', icns_dir
         ])
     except FileNotFoundError:
-        print(error('iconutil not found') + ', using png2icns (without retina support) to convert the logo', file=sys.stderr)
+        print(f'{error("iconutil not found")}, using png2icns (without retina support) to convert the logo', file=sys.stderr)
         subprocess.check_call([
             'png2icns', icns_dir
         ] + [os.path.join(iconset_dir, logo) for logo in [