Old config files vs integration panel and customization panel

Hi, I feel like total noob now but I have been using HA for a long time 0.5ish. I run it on a mac server and have configured everything in the corresponding yaml files.
Lately things have started moving into UI based configuration. Is there any documentation on how the UI based config is handled with old classic configuration. Changes I do in UI is not written to my old yaml files and I cant find where “new” config is stored.

Any pointers to updated documentation is hugely appreciated.

All the new stuff is stored in the .storage directory.