Tao theme preprocessing breaks Plugin Manager search page

The Tao theme preprocessor functionality 'breaks' the Plugin Manager search page. This is particularly noticeable using the Rubik theme (as Administration theme, in conjunction with the Admin module) by wrapping the fieldset legend anchors in a span tag (see attached).

I'd be glad to address this issue with a patch, but since there are perhaps several ways to potentially address this issue I'd like to get some best-case directional suggestions. Any ideas on how best to handle this issue?