The recent outage for users of Mozilla’s Firefox web browser was caused by a Firefox update, the source code for which was inadvertently pushed to the Mozilla Add-ons Repository. That repository is not publicly available, so it was not possible for users to update their installations. Fortunately, a bug was introduced in the Firefox update which prevented the update from being installed. The bug was fixed when the update was rolled back. Users who updated earlier were protected.
The outage could have been worse, though, because the bug that was introduced in the code for the Firefox update was in a feature of Firefox itself that allows users to block certain updates until a later time. In the case of Firefox, that feature was used to block the update that caused the outage. If a similar situation occurred in the future, users would not have a way to block the update that causes the outage. That feature is available in other web browsers, but it is not as advanced or robust.
The outage could have been worse, though, because the bug that was introduced in the code for the Firefox update was in a feature of Firefox itself that allows users to block certain updates until a later time. In the case of Firefox, that feature was used to block the update that caused the outage. If a similar situation occurred in the future, users would not have a way to block the update that causes the outage. That feature is available in other web browsers, but it is not as advanced or robust.