1840 - add override url + disable local fallback
1840 - add override url + disable local fallback

they are both in Tor 7.0.2.
With .url.override set, media.gmp-manager.url is never used (but let's keep it anyway)
source: https://dxr.mozilla.org/mozilla-central/source/toolkit/modules/GMPInstallManager.jsm#66

Since ESR52 it is not enough anymore to block pinging the GMP update/download server.
There is a local fallback that must be blocked now as well. See: https://bugzilla.mozilla.org/show_bug.cgi?id=1267495.
ghacksuserjs/ghacks-user.js,ghacksuserjs/ghacks-user.js