Discard Service Worker by Maxi9090

This extension is a single tiny background script that purely unregisters a website's service worker registration when:
- no open tab is using a website with a service worker.
- leaving a site in the same tab.
- closing the last tab with a service worker.
- starting up the browser (because no websites are loaded on startup).

Firefox like all browsers keeps every service worker registration installed forever unless you clear cookies and site data, which also logs you out of your accounts. Service workers for sites you have left can wake and run in the background, using memory and network. This extension solves both, and doesn't need any manual intervention.

Permissions

This extension only needs two permissions to work:
- Navigation activity (webNavigation) reports which pages and frames are open.
- Browsing data clearing (browsingData) is used only to remove service worker registrations.

Those permissions can do more, but this extension only uses webNavigation to read frame URLs to decide when a site is no longer open, and browsingData to pass the service workers flag. No other data types are ever touched. Neither permission can read page content or change network requests.