Extension Specification Authoring & Publication

Hi,

Is there a preferred method for authoring and publishing HTML extension
specifications within W3C infrastructure?

Notably, there are Mecurial[1] and Github[2] repositories, should an
extension provide a patch to the master specification or the extraction of
differential sections and publication of a new document?

Thanks,
Cameron Jones

[1] https://dvcs.w3.org/hg/html-extensions/
[2] https://github.com/w3c/html