In #Guix we’re discussing a deprecation policy to serve both as a guideline for contributors and as a “contract” with users:
https://issues.guix.gnu.org/72840
The latter is important: users should know that they can trust Guix to not change overnight without prior warning, that scripts, manifests, OS configs, etc. won’t break unexpectedly.
If you’re a Guix person, now’s the time to make your voice heard!