It's deploying a branch to production. If you think about it, this is completely the example of "master is production-ready" idea. We care so much about keepin

It's deploying a branch to production. If you think about it, this is completely the example of "master is production-ready" idea. We care so much about keeping master deployable, that if we have code that may have issues and need to be rolled back, we deploy just the branch. That way if things break, you can "roll back" to master and everything is good again.