==== What is the problem?
There are circumstances under which a contributor's username is hidden.
Currently, the revision details popup shows nothing for the username and the User_talk and Special:Contributions links are invalid. See screenshot.
I don't think we are likely to see this problem often. It would require a contributor's username to be hidden but not have their revision reverted. Unless a user explicitly goes to the old revision (like the example in the reproduction steps).
**Acceptance Criteria:**
* If there is a hidden contributor, display the following: "//(Username or IP removed)//"
* No talk page or contribs link needed
==== Steps to reproduce problem
1. https://en.wikipedia.org/w/index.php?title=Cadeyrn_Neville&oldid=597866123
2. Turn on WWT
3. Click any word in the second sentence
==== Screenshots (if applicable):
{F30236901}