You can clone with
HTTPS or Subversion.
I just tried to edit http://prose.io/#michael/documents/blob/master/prose-0-3-0.md, I could edit the text, but could not save, it just 'spun'.
I assume that is because I don't have permission to edit. What error message options are there for this situation?
Ohh kk. Will check that. Maybe an edge case that hasn't been covered. You should get a proper 'unauthorized' error message.