I use Qutebrowser and I always forget the actual application name to run it.
When I use terminal and want a default browser to open up to Qutebrowser I have to change it.
xdg-settings get default-web-browser will show you the current default browser. Your might show up as chromium.desktop
if you want to switch it to Qutebrowser
xdg-settings set default-web-browser org.qutebrowser.qutebrowser.desktop