Web App Maker wót Errno Ebadf

Click the extension button and two options will appear:
- pop out current tab
- copy web app link

The web app link can be used to make bookmarks or shortcuts to open sites like Spotify, Element, etc... so they use Firefox but it feels like a Progressive Web App (PWA) instead.

The web app link is of the form moz-extension://[uuid]/app/[site_to_open]. This link is specific to an instance of the extension and only exists for your browser. If you uninstall the extension the links will not work. If you reinstall the extension, old links will not work.

The decorations are hidden by using the javascript API browser.windows.create() with type="popup" (see https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/API/windows/create#type).