You have had kernel panic. It probably has nothing to do with Firefox. For more information read Resolving Kernel Panics. Usually, KPs are related to hardware rather than software.


Jon

macOS 11.7.10, iMac Retina 5K 27-inch, late 2014, 3.5 GHz Intel Core i5, 1 TB fusion drive, 16 GB RAM, Epson SureColor P600, Photoshop CC, Lightroom CC, MS Office 365