I’ve updated my install from the master branch of V11.
I get a pop-up “Not Found The resource you are looking for is not available” about 8 seconds after I open an Item document.
There is a single log entry in /logs/web.error.log which appears when I press OK on the pop-up.
fatal: Needed a single revision
There are no logs entries created when I open the Item or when the pop-up is created, only when it is cleared.
I had followed nearly all the instructions, but not the final clearing my browser cache. I was so focused on the server side of things I forgot the client! Ctrl+Shift+R