Extension:TitleKey

The TitleKey extension provides a case-insensitive title prefix search. It uses a separate table for the keys, so if it works cleanly it can be deployed without an expensive rebuild of core tables, and dumped when Wikimedia gets a nicer backend through Extension:LuceneSearch (pre 1.13) or Extension:MWSearch (1.13+). This extension is not necessary if you are using CirrusSearch.

For the average site administrator, the benefit of this extension is that it allows search suggestions (e.g. from Opensearch API) to be case-insensitive.

Troubleshooting
If you put, e.g.,  you might get "Failed opening required '/home/stauffenbergssh/extensions/TitleKey/../../maintenance/Maintenance.php'"". To fix it, you would put a copy of the Titlekey directory under your wiki extensions folder (rather than in an extensions folder outside of webroot).