Manual:CleanupTitles.php/en

Details
cleanupTitles.php is a maintenance script located in the  directory that can be used to clean up broken, unparseable titles. The edits will be attributed to the user called Conversion script. This script is rather useful for cases in which someone has added a new interwiki prefix (e.g. ) to the  table and thereby caused mainspace pages with ambiguous titles (e.g. Commandos: Behind Enemy Lines) to become inaccessible. Likewise, the script can be used to process changes in that rendered previously valid page titles inaccessible. Note that is often a preferable option, if the goal is to move pages into their proper namespace.

Also note, this script does not support fixing encoding issues (e.g. Pages that are not UTF-8 NFC) at current time.

Checking and fixing bad titles
Fixed pages are moved to Broken/ (where is the cleaned up version of the broken title)