xdg-settings gets the award for least intuitive interface ever.

• xdg-settings get default-web-browser was firefox.
• xdg-settings set default-web-browser qutebrowser.desktop is quiet
• xdg-settings get default-web-browser is still firefox.
• man page says that the errors are shown as …return code??
• echo $? returned 2, which is file not found basically.
• Bonus points for not accepting -h (only --help), and having --list as a parameter, but get/set as commands.

> xdg-settings set default-web-browser

xdg-settings: invalid application name

oh well.