I want to put some custom information in the content area of book pages (so, after the author info and before the add child page, etc. links). In the node template, the content comes in with both the body content and the following links already merged. I've dug through the core template directories and I can't find the template for just the body content itself. Anyone know what it is? Thanks!
The correct answer is you need to look at how to turn on twig debugging Please read and understand:
once you have fully read the above and have set it up you will be able to find the correct template and copy the default form the core to your theme and edit away.