Where are proposed extensions announced? (e.g. historical data)

In looking at the table of proposed extensions that Dan posted a link to, I
noticed a proposed extension for historical data.  That kind of surprised
me since it's an area that I'm interested in and I thought I would have
remembered an announcement about someone working on that kind of extension.

Did I miss the announcement here or is there another list that I should be
following instead?

This effort seems pretty advanced since it's been underway for six months
and was "launched" with an announcement by the Mormons in the keynote at
their RootsTech conference a month ago, so perhaps it's all a fait accompli
at this point, but I'd like to make sure that I don't miss similar future
efforts.

Tom