Install [the dependencies](https://github.com/kovidgoyal/kitty#dependencies)
using your favorite package manager. Build and run kitty [from
source](https://github.com/kovidgoyal/kitty#install-and-run-from-source).

Make a fork, submit your Pull Request. If it's a large/controversial change, open an issue
beforehand to discuss it, so that you don't waste your time making a pull
request that gets rejected.

If the code you are submitting is reasonably easily testable, please contribute
tests as well (see the `kitty_tests/` sub-directory for existing tests, which
can be run with `./test.py`).

That's it.