If a maintainer wants to stop or leave, it's cool. We'll gladly point to the project's new home and keep an archive of the old history.
If a cookbook is for software that's no longer feasible to keep running, like old open source, old commercial stuff, anything that can't be downloaded; then we update the cookbook
README.md to mark as deprecated.
If a cookbook seems entirely unused, we may want to stop claiming it is maintained. In that case, we'll update the cookbook
README.md to mark it as archived.
If someone objects to the project moving and wants to continue maintenance under the sous-chefs, we add a prominent link to fork on the readme and continue development. People are generally not idiots, so if they have a reason to leave us we should support them.
Otherwise we update the cookbook
README.md to mark as relocated, at least pointing where the cookbook went.
Regardless of how a project leaves the Sous Chefs, we will keep a copy of the history available so anyone looking for it will know what's happened.
We keep a copy of the cookbook's history available for at least a year.
After that, we may delete the repo if we have some reason too. But practically we'll be trying to keep a record of the code's history for as long as we can.