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+).

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).