FFv3 (GRE 19.x) already supports html5 (not fully, but then again I don't think any browser fully supports html4 either, maybe not even 1, 2, or 3 for that matter). Seamonkey v2 also usues GRE 1.9x, so once KM switches over to the new GRE it'll support html5 too.
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"People who live in glass houses ....should close the friggin curtains!"