This guy also forces secp521r1 (the NSA curve which is impossible to implement correctly, is unsupported by Chrome and eventually by Firefox, and is dog slow) instead of using DJB’s x25519. This is what roleplaying as an SRE looks like.
https://bugzilla.mozilla.org/show_bug.cgi?id=1128792
so far, absolutely no justification for Google to drop P-521: https://bugzilla.mozilla.org/show_bug.cgi?id=1129077
https://security.stackexchange.com/questions/100991/why-is-s...
If you look at the telemetry for last actual Firefox release, only 8 (yes, eight!) out of 1.67 BILLION handshakes used a P-521 curve. This is a good indication that P-521 isn't needed, at least for certificates verified by web browsers.