When migrating a did:web identity from another PDS using Tranquil's built-in migrator, trying to select Passkey as the authentication method and then continuing results in a error message "BYOD migration requires a did:plc or did:web DID".
However selecting Password as the authentication method lets me progress as normal and successfully complete the migration, and I can then later add a passkey through the dashboard.
reading this I'm fairly certain I immediately know what the regression is, thank you. In the meantime your new did:web account could be made passkey-only after the fact in the account manager UI by adding a passkey then removing your password!