makes a lot of sense, thank you for this RFC.
I only have one question, do you mind outlining where/how you'd wire OnNetworkDespawn events on the server and clients?
Some neighbor codes and/or call-stack to get to the OnNetworkDespawn would be great!

I added this to the reference level section of the RFC. I also plan to do some small refactoring around how NetworkStart is called (no behaviour changes just throwing out unused legacy code)

Surley this should only occur if IsSpawned is true? Otherwise you could have a NetworkObject that is never actually spawned, (thus OnNetworkSpawn is never called) but OnNetworkDespawn is called.

OnNetworkDespawn is very interesting to me, would this also give me room to gracefully fade away the object over some time on client or the object would be destroyed anyway before I could fade it?

You won't be able to use OnNetworkDespawn for this specific use case because MLAPI would still force destroy the object after. In this case you would need to implement a custom destroy handler to override the destroy logic of MLAPI:
https://docs-multiplayer.unity3d.com/docs/advanced-topics/object-pooling

@TwoTenPvP Yes, correct this will only occur if IsSpawned is true.

@LukeStampfli, Makes sense. thanks for pointing out the object-pooling.

Would OnNetworkDespawn also be called when server runs Show/HideNetwork?

Currently NetworkShow and NetworkHide spawn/despawn an object on the client and would trigger the OnNetworkSpawnandOnNetworkDespawn` functions