This adds a major custodian’s operational requirements to the open design process and makes concrete how protocol choices affect institutional custody, ordinary wallets and migration sequencing.
Coinbase had disclosed internal preparation, engineering support and a September workshop, but had not published this consolidated Bitcoin-specific design brief.
The paper is public input to discussion—not a final Coinbase position, BIP endorsement, specification change, implementation merge or deployed custody capability. It names P2MR and P2TRv2 as flexible candidates rather than selecting one.