Comment by perching_aix

This blogpost covers a workaround they discovered that would have let MV3 extensions access important functionality that was not normally available, only in MV2.

This workaround was fixed the same year in 2023 and yielded a $0 payout, on the basis that Google did not consider it a security vulnerability.

The conclusion then is that uBO (MV2) stopped working for me today after restarting my computer, I suppose.