Karplusplus
Kar+plus generator v.2
Robert Karplus was a noted physicst and educator. https://en.wikipedia.org/wiki/Robert_Karplus
Kar+plus software project enables a group of physics teachers to jointly maintain an important part of his legacy.
This collaborative software enables many-to-many - many authors and many versions of the book. The intent is that there is not a single definitive book even at a point in time. The user can provide a "recipe" that generates a specific Kar+plus derived edition. I might ask for the first and third chapters with my colleague's annotations with my second chapter and the exercises selected as 4 stars and above for strong math ability at the 7th grade exported in PDF and epub3 formats. Or I might ask for a pdf of only the illustrations and section heads because I am using them for slides.
Ideally The same API -- the similar "recipe" could span multiple books on introductory physics and compare their approaches for given chapters with commentary. The same infrastructure would allow different physics text to share exercises while systematically tracking the copyright and IP for the community contibuted exercises and commentary.