kitty/CONTRIBUTING.md

Install the dependencies using your favorite package manager. Build and run kitty 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.