iOS 18.4 introduces the new WKWebExtension API to support extensions in WKWebView. However, for extensions that have migrated to Manifest V3 and use an extension service worker as the background script, it's currently not possible to inspect them through Safari.
This is only thing I can see, I don't know how to inspect the details of the "background.js"
I'm wondering—has this changed? Is it now possible to inspect extension service workers?