Found some easy STRs confirmed also by email with a reporter: - Have the `Swift Dark` Substratum theme Firefox overlay applied for the previous 67 release - Update to 68 - Next app starts would result in an immediate app crash with the above stack trace Solution to this is to update the Substratum overlay for our application. The solution proposed in comment 5 (the best we could do) would in fact prevent this sort of customization so it isn't feasible. Based on comment 5 and this I'll close this as WORKSFORME.
Bug 1555332 Comment 8 Edit History
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Found some easy STRs confirmed also by email with a reporter: - Have the `Swift Dark` Substratum theme Firefox overlay applied for the previous 67 release - Update to 68 - Next app starts would result in an immediate app crash with the above stack trace Solution to this is to update the Substratum overlay for our application. The solution proposed in comment 5 (the best we could do) would in fact prevent this sort of customization so it isn't feasible. Based on comment 5 and this I'll close this as WORKSFORME. This issue is entirely caused by an external modification and can also be resolved entirely by the user.