Using OneNote's Onetastic I've been able to inspect the raw XML structure of the notebooks. The REST API returns the page information as HTML, but is limited (no support for ink, shapes, OCR, etc.)
Is there some way to get the raw XML of the page? Perhaps from the OneDrive API?
Thanks in advance!
Unfortunately, there isn't. You can only get HTML.
I do encourage you to go into our uservoice site and create requests for whetever type of content we don't support: https://onenote.uservoice.com/forums/245490-onenote-developer-apis
For example, there is one for ink. https://onenote.uservoice.com/forums/245490-onenote-developer-apis/suggestions/5657688-ink-support-in-the-api