Naturally, a few days after I argued that our deletion policy should be less rigorous... :-)

Here's what seems to have happened: someone, somehow, managed to upload an image that appeared in the logs with a blank name. There's a part of the script that fills in the title "Main Page" if no title is given for some commands (that's so that, for example, "wiki.phtml" gets you the main page if you don't specify a title). Apparently, that caused the system to think I wanted to delete the main page.

This is probably a bad idea.

I've locked the database and disabled the delete function for now. When I finish restoring the main page from the tarball I made yesterday, I'll unlock the database, but I'll leave delete disabled until I can make it safer.