Looks like a gift from early April. Not seeing a bug filed yet, so here's one. NEWS https://cgit.freedesktop.org/polkit/commit/?id=ed06baed179166389d536420a6fc532781d48178 among other things, port to mozjs 52.
https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=db7be444bafe171f9077683ffdcec6e252a8394a