We very much appreciate any contributions to the project, you don't even necessarily need to do any coding.
For code submissions we accept GitHub pull requests to the develop branch. If the update will force users to change their configuration, or take any other manual actions it should bump the version number according to format specified here.
You can find a guide here for forking a repo and making a pull request. Feel free to mark a PR as a work in progress and submit it early, a PR is a good place to follow progress and get feedback.
If you really want to make us happy, make sure your changes pass pre-commit checks. It has been integrated in the CI pipeline. For instructions on how to run it locally, please refer to Setting up pre-commit.
Any & additional unit tests are also huge bonus.
GitHub repo is located at:
https://github.com/Flexget/Flexget
Development tutorials and documentation:
https://flexget.readthedocs.org/en/latest/
Feel free to drop in to chat.