Ever tried uploading a .html file to a Mediawiki installation? Well, I did and got:

    Permitted file types: png, gif, jpg, jpeg, pdf, txt, gz, bz2, deb.

OK, let's add .html to the wgFileExtensions array. Let's try again:

    Files of the MIME type "text/html" are not allowed to be uploaded.

Sigh. OK, so we have to edit wgMimeTypeBlacklist as well, or just disable this damn thing with wgVerifyMimeType. That should do it, right?

    This file contains HTML or script code that may be erroneously
    interpreted by a web browser.

Are you kidding me? And yes, I did check the "Ignore any warnings" box. Turns out that this is still anresolved issue and wgDisableUploadScriptChecks did not make it into trunk yet.