privacy.firstparty.isolate.restrict_opener_access is a pref for First Party Isolation that relaxes the protections of FPI by allowing access to window.opener across first party domains.
It was created because in Tor Browser's initial FPI patch, they allowed this by mistake, and we wanted to keep backwards compatibility. Except it was ever actually used; although it did solve at least one FPI login breakage flow that relied on that opener access. Since it's been used in practice by anyone we know of, and it complicated some codepaths, we intend to remove it. -tom _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
