While I’m not sure this deserves a “policy” since I could envision a scenario where one might want to use the former origin for some reason, I think if you have a package that others are using and then move that package into core, one strategy would be to Build a new release in the former origin that:
is just an empty package that takes a dep on the core package (library packages only)
Emits a warning in the build notifying on the new core package
emits output in the init hook stating that the users should use the core package (service packages only)
Make it clear in the old readme of the core package
Make the package private in builder so it will not show up in searches
I’m pretty sure no one is using my example case yet, it’s only been published as long as the PR has been open… so probably safe to just disappear it but I @mwrock’s approach for anything that’s been in the wild on its own for a bit