If the extension uses manifest v3 and a background script in the form of a service worker, then in Safari it is not possible to open the background script debugging window. If I expand the Developer menu in Safari, there is nothing under Web Extension Background Data (or disappear after click), which is an error. In other browsers (Edge, Chrome, Opera, Firefox) this works correctly.
If I switch the background script back to non-persistent script mode, everything works fine and from the Developer menu and the Web Extension Background Data submenu I am able to open the background script debugging window for the extension. Am I doing something wrong?