Interesting. I see a gotcha though: > Validating an ARC chain only makes sense if the receiver trusts the ARC signers. In fact, an ARC chain can be counterfeit

Interesting. I see a gotcha though: > Validating an ARC chain only makes sense if the receiver trusts the ARC signers. In fact, an ARC chain can be counterfeited,[3] so ARC processing applies when receivers trust the good faith of ARC signers, but not so much their filtering practices. Is there any documentation on how GMail and Hotmail onboard a ARC-using domain? Their documentation is very... sparse.