When adding configuration (e.g. ruff rules, pre-commit hooks, CI config, etc.) if there is existing config, it is not obvious how to interact with it. Should we replace it? (probably hardly ever!) Should we merge it together with the default in some way? (Tricky, but good for updating to latest best practice.) Should we just give up and leave the config alone (very easy, potentially missed opportunities.)

Some thought needs to go into this, and its ramifications need to be reckoned for the three examples mentioned above.