Copying prefabs without using packages

I can't think of a reason why it should work with scenes but not with prefabs. What are the problems you experience? Do you copy the meta files as well?

Yes, the meta files are being copied as well. The problem is that the hierarchy of the gameObject, or the deletion/add of one of its component will not be "echoed" to the other project instances, although the .prefab and .meta files being copied as soon as modified.

Is there anything I'm missing about prefabs?

I guess there is something you are missing about metafiles. As I understand Unity automatically assigns some signatures to assets and operates with them so you can change names and modify those files but the links to them will keep working. So probably you can not just copy-paste those assets with metafiles because dependencies will be broken.

As I understand Unity automatically assigns some signatures to assets and operates with them so you can change names and modify those files but the links to them will keep working.

Exactly. But this signature isn't hidden or magic. Its the GUID assigned in the .meta to the whole prefab file together with the FileID within that .prefab to reference parts of the prefab (e.g. reference its transform component). All these informations are inside the meta or prefab file.

What Unity could have problems with are duplicated GUID's. If you have the same GUID in the project you are copying the prefab to, then unity will emit a warning and assigning a new random GUID.

That is as true for prefabs as it is for every other GUID (scenes, scripts, even folders)

hierarchy of the gameObject, or the deletion/add of one of its component will not be "echoed" to the other project instances

If they are still intact prefab instances (blue in the hierarchy) then this should work :(.

Did it here too a couple of times and copying prefabs (together with their metas) will reflect correctly as long as you don't change the File ID's (there are only few operations that can change an file ID and this will break all links - even the one in the original project. Like removing a referenced component and later adding it again will break references to that component.)

$$anonymous$$aybe you set up a tiny test case and report this as a bug.

You are using forced text format, right?

You are using forced text format, right?

Nope, I wasn't aware there was such a thing... setting this up right away, I'll keep you posted. Thanks!