To add to what @awesomerobot posted:
Our nomenclature is a bit different than other software companies, but what it means when we release a beta is we’re releasing a new incremental version. We’ve said, “That’s enough changes for now. Let’s notify sites about new updates.”
So for us, a beta is a minor version bump, and a version is a major version bump. They’re checkpoints we give ourselves to celebrate the work we’ve done. We tend to release two major versions a year, but it all depends on feature development and the like. We’re not really into fake deadlines.
Regarding the branches
Stable/beta are not necessarily any more “stable” than tests-passed. It’s more the idea that the bugs are known. With tests-passed there may be new bugs introduced then fixed a few commits later.
Tests-passed is not much different than most other software releases out there, which usually release small changes every two weeks. We commit new changes almost daily instead, and they’re available via tests-passed.