I'm running a GNOME/Wayland desktop. With other browsers (GNOME Web, Chromium) I can open so-called app instances. These typically:
- open at a preset URL
- are limited to a single tab
- have reduced/no chrome
- cannot browse to any other domain/subdomain
- and, if I click on a link to a different (sub)domain, it opens in the default browser instance (whatever that happens to be)
How can I achieve features 4. and 4.1. with Firefox? (The rest are unimportant to me.) If a plugin is required it should have an FSF-approved license, but I'm hoping there's a setting buried somewhere.