Did you bother to even open the spec or were you too busy making assumptions? Here is a link in case the you missed the one on the site: http://mailmarkup.org/mail-documentation.xsd

I am going to make the baseless assumption that your intentions were well placed, and happily await a contribution of prior art.

EDIT: My lawyers have deliberately asked that I not transcribe the claims in the patent application, but its really not hard to figure out from looking first at what the language does differently from the spec and then glossing over the claims in the patent application. I put this stuff online myself years ago, because I have nothing to hide and want nothing more than to ensure the software is valid and novel. Please feel free to prove otherwise, because either way you are contributing to a software project.