Instead of displaying ipb_address directly.
It seems old Extension:Renameuser didn't update ipb_address correctly, leaving many incorrect ipb_address values in database.
This also affects newly renamed users (due to job queue).
The method of trying to join user table is already used in revision table etc.
Version: 1.23.0
Severity: normal
See Also:
https://bugzilla.wikimedia.org/show_bug.cgi?id=57482
https://bugzilla.wikimedia.org/show_bug.cgi?id=3279