I know current dev channel builds come from the co_release branch, however, I would like to know when they switch to another branch. (Say co_refresh or rs_prerelease)... Is there a way to do it? In the early days the branch would appear in the Windows Registry... but that's no longer the case.
Sorry, I meant the branch from which builds are getting pulled. Not the branch of the currently installed build. For example: I'm running 21387.1 from co_release, but then they switch insider machines to co_refresh... However I won't know about this change until I get a build from co_refresh. In the past, I would be able to check this by looking at the registry, you could know in advance when they switched branches.
"you could know in advance"? You can "GUESS" the upcoming Insider Preview build by user language's "Local Experience Pack" from Store, e.g. English (United States) Local Experience Pack.