Proposed changes to more fully support RFC 2369, "The Use of URLs as Meta-Syntax for Core Mail List Commands and their Transport through Message Header Fields" -- i.e. the List-*: headers.
No documentation update is included - will add when there's consensus. (I've been wanting this a long time, and now that I'm changing jobs and have to unsub from a ton of mailing lists it's on my mind more heavily.)
