Support 'Apps for Office' to allow custom TaskPanes within OneNote apps.
This is already available in OneNote Online – but not in the rest of our clients.
Jiří Matějka commented
Hi, can you share update if this is still planned in the OneNote UWP App?
Btw there is a post with the same topic, having 300 votes here on UserVoice: https://onenote.uservoice.com/forums/245490-onenote-developer-apis/suggestions/34143199-onenote-uwp-add-in-api
For example, let's say I wanted to see a user's highlights, and then I could process that data and return only the elements that matter.