Hi, I'm replying mainly to restore the thread's subject line back from ‘none’. Z572, please try to keep an eye out for this if this is something your MUA likes to do.
Anyway, the ‘guix time-machine --{commit,branch}’ thing would need to be tested before/if the GCD is accepted, but should not affect its passing. If ‘guix time-machine’ does check whether a given COMMIT is on the given BRANCH, it should not emit a fatal error, merely a warning. If it doesn't check, that's fine. That's probably not free-as-in-resources. If so, then whether Guix should silently ignore BRANCH or warn that it's meaningless is out of scope here. Kind regards, T G-R Sent on the go. Excuse or enjoy my brevity.