Version check for new stable release?

[RBoy]

I was looking at this post about using a specific version:

How would I install a certain (old) version of Discourse

Checkout the same version of discourse_docker that you use on your other server, maybe copy your app.yml from the old server and make the necessary changes. Also in app.yml, change the version from tests-passed to either a tag (e.g. v2.5.0.beta7) or use a git commit hash.

When I look at github I see stable or tests-passed branches (not tags). However I do see a latest-release tag. What’s the difference between stable (branch) and latest-release (tag)?