If its getting read as zip couldn't you just add "pptx" to the includes/mime.types file on the application/zip line? This is how I get ppt to be recognized since it is read as "msword" and so I add "ppt" to the applications/msword line.
No. MediaWiki rejects zip MIME type uploads (for good reason). The (incomplete) hack in my previous email still blocks most zip files from being uploaded. Zip files without extensions can probably be uploaded because of the "$ext === false" check though (I didn't test for this).
For some reason MediaWiki checks the MIME type twice; once with the extension passed to the function, and another time without the extension passed. The "$ext === false" part was required to get around that. Is this how the checks are *really* supposed to work? I really didn't understand that; why check twice?
V/r,
Ryan Lane