As reported on the dev list, the OAuth authorisation screen seems to have stopped showing any details of the requested access. Instead of:
it is now showing:
I haven't looked at the cause yet, but I guess @samanpwbb's redesign work is the most likely culprit.
So the problem is that the missing information has been put in the new heading block, but that screen uses the slim layout in app/views/layouts/slim.html.erb which does not currently display the heading block.
Other things (like the login screen when doing OAuth authorisation) also use that layout instead of the normal one and hence are likely to fail in the same way.
I've pushed 773f145 to fix this for now, but it could probably do with being looked at properly...