In my work as a teacher it would be very helpful for me, if I could choose one of my bookmarks, open the bookmark properties, click a button and have a little qr-code window I can show to my students, so they can open same page for their work ....
A built-in "share as QR code" option would be really useful, they could probably customize it so there is a fox or Firefox logo in the middle as Google does with their dinosaur QR codes on Chrome.