How to include rst-files which themselves include other rst-files?

[nunupeke]

I have a jupyter book consisting of tutorials (written in jupyter notebooks) and an api reference (rst-file). My _toc.yml looks like this

- file: index
  sections:
    - file: tutorial_1
    - file: tutorial_2
    - file: api_ref

The api reference rst-file itself includes other rst-files that are generated using the sphinx autosummary extension. When building my book, I get the warning "Found a content page that is not in _toc.yml" for every file that is included by api_ref.rst. Is this intended behaviour (i.e. am I doing something wrong)? Or can / should I silence these warnings?

In the final output, all rst-files are included Ok.