I went through the last 6 months of crash volume with this crash signature, and, for the crash reports that contain a URL that's publicly viewable (not behind a login wall etc), I confirmed that I don't crash (and don't see any obvious brokenness) in a build with this bug's patch and bug 1989368's patch. So I think these two bugs' patches address all or nearly-all of the crash volume under this signature.
Bug 1990034 Comment 11 Edit History
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I went through the last 6 months of crash volume with this crash signature, and, for the crash reports that contain a (privately-included) URL that I can actually load (it's not behind a login wall etc), I loaded the URL and confirmed that I don't crash (and don't see any obvious brokenness) in a build with this bug's patch and bug 1989368's patch. So I think these two bugs' patches address all or nearly-all of the crash volume under this signature.