Looking around more, it looks like HREF really is/was a Macintosh resource type... but it is still a URL. Basically it's a text track in a Quicktime movie that contains a URL.
To make this interesting enough for you guys to read, here it is described in terms of being used as a Quicktime-based exploit!
To make this interesting enough for you guys to read, here it is described in terms of being used as a Quicktime-based exploit!
http://www.gnucitizen.org/blog/backdooring-quicktime-movies/