As a workaround, please try right-clicking on Firefox and selecting Open. This is most likely due to Build 68 not being Notarized. This would affect 68 and not 67 because macOS 10.15 uses the application build date to determine which applications are required to be Notarized in order to launch. According to the WWDC presentation[1] around 8:00, all software "signed on built after June 1st" must be Notarized. We have enabled Notarization on build 69 and plan to uplift this at some point in the future. 1. https://developer.apple.com/videos/play/wwdc2019/701/
Bug 1563631 Comment 5 Edit History
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~~As a workaround, please try right-clicking on Firefox and selecting Open.~~ This is most likely due to Build 68 not being Notarized. This would affect 68 and not 67 because macOS 10.15 uses the application build date to determine which applications are required to be Notarized in order to launch. According to the WWDC presentation[1] around 8:00, all software "signed on built after June 1st" must be Notarized. We have enabled Notarization on build 69 and plan to uplift this at some point in the future. 1. https://developer.apple.com/videos/play/wwdc2019/701/