I (@marcoscaceres) tried to implement the spec changes and managed to identify some critical issues with the PR:

• We need to introduce a new typedef (DigitalCredentialPresentationProtocol or DigitalCredentialIssuanceProtocol) DigitalCredentialsProtocol;
• DigitalCredential's protocol member's type should be DigitalCredentialsProtocol, not DOMString.

Originally posted by @marcoscaceres in #401 (review)