When editing a content without TinyMCE, no way to embed an image is available. I have not tested how it behaves for a content in FORMAT_MOODLE or FORMAT_MARKDOWN migrated from 1.9.
1. turn HTML editor off in your profile
2. try to create a Page
There should be a way how to embed an image, for example via a file picker that would allow me to copy the link to the image in the draft area.
There is no way to embed an image.
This breaks backwards compatibility (this feature existed in 1.9) and makes File API completely unaccessible via any other way than TinyMCE + FORMAT_HTML. Or did I overlook something and there is an obvious way to do it?