It's hard to know what is happening here without seeing the project you are trying to build/use. Is it possible to include that in a bug report on https://feedbackassistant.apple.com? Thanks!

Safari does currently not support captureTab, if you could file feedback on https://feedbackassistant.apple.com asking for this and explaining the use case that is desired, that would be very helpful. Thanks!

These are great pieces of feedback. Can you please file them on https://feedbackassistant.apple.com? I think there are three distinct pieces of feedback here. webRequest not working with non-persistent background pages raw/binary support for webRequest request events webNavigation events not being fired for navigation Re: #3, what version of Safari are you testing this on? Safari 17 had a change where your extension is now required to have permission to access the URL that the webNavigation event would be generated for. A sample extension reproducing this would be ideal for this bug report. Lastly, when you are reproducing #3, do you have "Preload Top Hit in Background" turned on in Safari Search Settings?