I went to a user's contributions page:
https://en.wikipedia.org/wiki/Special:Contributions/Citation_bot
I then selected Wikipedia namespace and clicked "Search", which should have taken me to
https://en.wikipedia.org/w/index.php?title=Special%3AContributions&target=Citation+bot&namespace=4
However, after a period, the following error was thrown:
A database query error has occurred. This may indicate a bug in the software.
Function: IndexPager::buildQueryInfo (contributions page filtered for namespace or RevisionDeleted edits) Error: 0
Note: https://en.wikipedia.org/wiki/Special:Version shows MediaWiki 1.23wmf5 (rMWd7c6f6cdefdc) which is not in the "Version" selection list above.
Version: 1.23.0
Severity: normal
See Also:
https://bugzilla.wikimedia.org/show_bug.cgi?id=58324
https://bugzilla.wikimedia.org/show_bug.cgi?id=60618