I would like to have ruff cache go in $XDG_CACHE_HOME/ruff if it's configured (by default it could go in $HOME/.cache/ruff).

This is according to the XDG Base Directory Spec for user directories.

Is this already an option and I missed it in the README? (recently started the journey to clean up my home directory)

Thank you for your work on ruff :) 🙏