In Firefox, anyway, this would work with CSS declarations like this:
table[cool=cool] { background-color:##aaaaff; }
And everything is done with XHTML-compliant attribute formats. So, they're trying to overload the attributes for certain tags with semantically-based ones ... it won't work across-browsers, but it should, and if it did it wouldn't be the absolute worst thing I've ever encountered. You could mix and match little pieces of desired behaviour/appearance without having to use multiple class declarations or re-use a bunch of code in your CSS selectors ... it would be kinda nice if this *did* work reliable cross-platform.
The other way it would work is with an XSL transform ... it would be like an in-house XHTML flavour that made it easier to reuse those grid controls and so on (whatever they do).
So, well, yeah, it's pretty WTFy, but the idea isn't completely outrageous ....