As far as I can see there is no ‘edit raw html’ possibility in Prosemirror, or did I miss some plugin?
Would it be easy to add this?
This is not something that the library is going to provide. You could provide such a mode with another editor, such as CodeMirror, on your side, if you need it.
I had this worked up locally at one point ala the markdown demo. It was fairly simple, but also a bit finicky. We’ve been burned enough with this sort of “mode switching” in other editors/cms setups that we’ve backed away from it for now.