While reviewing some other code, I went in and started ripping up some of the file type & validity checks in MediaWiki's upload system, as they've been driving me nuts for some time.

One quick subproject was tossing in an XML well-formedness check for SVG files. For the curious, here's a report on the invalid files I encountered while testing this with files from Commons:

http://meta.wikimedia.org/wiki/SVG_validity_checks

-- brion vibber (brion @ wikimedia.org)