This is a quick reminder for myself about the open source Pressbook project. Based on WP and uses H5P extensions, the project site states:

Pressbooks is a book content management system that exports in multiple formats: ebooks, webbooks, print-ready PDF, and various XML flavours. The system is built on top of WordPress Multisite, and makes significant changes to the admin interface, web presentation layer and export routines of a vanilla WordPress install.

https://pressbooks.org/