V8 has a branches waterfall that intends to provide coverage for beta/stable release changes.

Historically, the builders on that waterfall have diverted a lot from
the main waterfall bots and the coverage is poor.

Duplicating bots manually is hard, but post-luci migration it might be
possible to share a subset of main waterfall bots with the branch
waterfall. Ideally we'd just have a simple config somewhere that
specifies which main waterfall bots are also available as beta/stable
bots.

The UI needs to be taught to distinguish builds on master and builds on
beta/stable branches, and e.g. there should be separate console-views
for those.