I'm fairly sure the changed by appears in the serialization before the data from webcrypto is written out, so this is probably due to changes elsewhere (indexeddb or structured cloning). In any case, after 6 years, I think it's safe to assume the relevant keys have been regenerated.
Bug 1348279 Comment 12 Edit History
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I'm fairly sure the changed byte appears in the serialization before the data from webcrypto is written out, so this is probably due to changes elsewhere (indexeddb or structured cloning). In any case, after 6 years, I think it's safe to assume the relevant keys have been regenerated.