As part of the broader Firefox 66 release, this version includes:
Prevents web pages from "jumping" while images and advertisements load. Mozilla Firefox Quantum v66.0.5
The primary fix in v66.0.5 addressed a remaining issue where web extensions were still disabled for users with a master password set. As part of the broader Firefox 66 release,
Allows users to authenticate on websites using facial recognition or fingerprints on Windows 10. System Requirements Firefox 66.0.5 System Requirements released on May 7
Automatically prevents websites from playing sound-enabled media.
A new ability to search through all open tabs via the tab overflow menu.
Mozilla Firefox Quantum v66.0.5, released on May 7, 2019, was a critical point update primarily focused on resolving a significant bug that caused browser extensions to be disabled.