The role moves around based on current availability.
@tractorcow has done most of the last releases,
but a separate team (headed by @dhensby) will be
responsible for 3.x releases.
There's not really much point to declaring a release maintainer,
unless there's disagreements in the core team where we need
an arbitrator. So far those conflicts have been resolved
on individual tickets (e.g. what should go into a release),
and the process for that seems to work well.
It was getting a bit lost halfway down the contributing/code instructions,
in between the detailed git instructions.
Also reordered the docs TOC for that folder by renaming the files.