Require Extended Validation Certificates for onion services to have CAB Forum Tor Service Descriptor Hash extension
Note: It is possible that EV Certificates will be deprecated soon, because all major browsers decided to remove "green bar" which used to be main EV indicator.
CA/B Forum EV Certificate Guidelines (version list, 1.7.3) requires EV Certificates issued for onion services to have CAB Forum[sic] Tor Service Descriptor Hash extension (2.23.140.1.31).
Tor Browser should check for this extension before displaying onion service owner below "Connection secure" in website info UI.
I'm not sure if it is implemented, but I have not found any commits implementing this.