Trying to achieve the trust you are is very interesting.

I put up a simple, installable, progressive offline app of this crypto here: https://semocracy.com/

This app doesn't yet contain the mediations you talk about of checking the sw code against a 3rd-party reference and warning when an update doesn't match the reference.

Even considering the limitation you discuss when the new worker terminates async requests of the old worker, checking a public log is useful -- do you have any code or boilerplate I could plug in to achieve that?

Also, would the following be useful? The worker stores the 3rd party log / reference at intervals in local storage, and then when updatefound occurs, it doesn't need to make a network request, it can check (not perfectly) if the new sw code matches the stored reference. Sometimes there will be false negatives because the reference updated before the sw checked, but I think there would be no false positives. As long as the new worker can't get to localstorage before the old one checks, could be okay.