There’s existing suggestions for those features:
- skip credits / outro → Feature sugestion: Skip Endings
- extract theme based on intro detection → Themes: Update the new intro detection functionality so it can be used to create the theme music for a show?
- extract intro/outro as actual (video) extras → that one seems new to me
- automatic chapters → Plex isn’t modifying your media; you can already do that e.g. using the MKVToolNix multiplexer
