mozilla/bedrock — pull request #2257 by alexgibson (2014-09-05 15:07:31+00:00)
Title: [fix bug 1060614] mozilla wordmark on homepage does not work in IE 6 & 7

This is the offending jQuery bug ticket (3 years old!): http://bugs.jquery.com/ticket/8740

Simplest solution seems to be just to avoid using jQuery selectors containing empty attributes. In the case of this particular selector, it's probably overly specific to begin with.