Not sure when this will be properly fixed on Safari but it's fixed on Safari Technology Preview (Release 115 (Safari 14.1, WebKit 15611.1.3.5)) for me so it'll probably get to Safari sometime soon-ish in the future, I'm not sure what their deployment cycle looks like. For now, just to unblock deploying my extension, I implemented a workaround for Safari which opens my site's homepage instead of the popup. I hope this helps!

Hey, in case it helps, I have the exact same issue with the same exact errors. I found another thread - https://developer.apple.com/forums/thread/651173 here that suggested it's just a cosmetic error with xcode and their app passed review. I just uploaded my app to App Store Connect and so far no issues. I'm assuming it'll pass the review as those entitlements are clearly supported by macOS. Good luck!

Just wanted to circle back and say that my app was approved with no issues so you can probably ignore those validation errors and be good to go.