"With respect to "Token Service Providers MAY require KeyProviders to register/onboard." - register with a third-party service such a clearinghouse, with the Token Service Provider itself, or both? What is the purpose of such registration (e.g., so that the Token Service Provider can restrict its interactions to trusted entities)?"
Creating an individual issue from the list in #26 in reference to: https://github.com/w3c/webpayments-methods-tokenization/wiki/Tokenized-Card
"With respect to "Token Service Providers MAY require KeyProviders to register/onboard." - register with a third-party service such a clearinghouse, with the Token Service Provider itself, or both? What is the purpose of such registration (e.g., so that the Token Service Provider can restrict its interactions to trusted entities)?"