You need to turn on the debug menu in Safari
grant full disk access to Terminal
run defaults write com.apple.Safari IncludeInternalDebugMenu -bool true
In the debug menu select Extensions > reset web extensions state
But I would like to know how to do this on iOS.
simplicio
Users receive reputation points by contributing quality content to the forums.
Posts include post and replies published on the forums.
Post authors can mark replies as Accepted to indicate successful solutions.
Apple Developer Forums admins can mark replies as Apple Recommended to indicate an approved solution
Post
Replies
Boosts
Views
Activity
I believe this is a bug in Safari.
Safari MV3 supports the background.page key (so-called 'Event Pages') which you might be able to use as a workaround. Try something like
In manifest: background: {page: background.html}
In background.html: <script src="my_service_worker.js"></script>
Since incorporating my "service worker" like this I have stopped seeing the error (touch wood).