https://www.mozilla.org/en-US/firefox/android/66.0.5/releasenotes/

66.0.5 Firefox for Android Release May 7, 2019
Fixed
Further improvements to re-enable web extensions which had been disabled for users with a master password set (Bug 1549249).

https://ftp.mozilla.org/pub/mobile/releases/66.0.5/
66.0.5来てる。