(4) Protocol Identifier

Too some extent you can compare the protocol identifier to the Protocol Key "brc-20" on Bitcoin and "drc-20" on Dogecoin.

The protocol identifier for Runes on Bitcoin is R. With Dunes, being the Runes protocol “bridged” from Bitcoin to Dogecoin, there is a strong argument to follow the logic from the already establised drc-20 protocol and set the protocol identifier to D, as of Dunes instead of R on Runes.