Specifically the HSTS-like behavior outlined by Section 8.5 of https://datatracker.ietf.org/doc/html/draft-ietf-dnsop-svcb-https-07 We understand that Webkit (or perhaps DNS infrastructure more generally in Apple OS's) implements general support for HTTPS records and has been querying them since 2020, but we are unfamiliar with and request a position on Webkit's support for the specific HTTP->HTTPS redirect behavior.