It requires work to keep things working, exactly the same thing.

The module proxy is used by default and requires no work. I don’t think what you’re saying makes much sense.

So there is some magic pixie dust that will fix url relocations for the metadata used by the proxy, without having anyone touch its configuration?

I think I’m missing something, because I’m pretty sure you understand the go module proxy (having seen you around here before) but I really don’t understand what problem you’re talking about.

If a module author deletes or relocates their module, the old module is not deleted or renamed from the module proxy. It is kept around forever. Code that depends on it to not break does not break.

If they relocated and you want to update to the new location, perhaps for bug fixes, then you do have to do a bit extra work (a find and replace, or a module level replace directive) but it’s a rare event and generally a minor effort, in my opinion, so I don’t think this is a significant flaw.

For most users most of the time they don’t need to think about this at all.