I just went through a long list of keyboard shortcuts for Firefox. One that I didn’t see that I would find useful is to press something like ⇧ Shift + ⌘ + C to copy the URL and then paste it into an email or message to send to someone. Does something like this exist?
Generic shortcuts -
F6
andCtrl+L
both get the URL selected.Ctrl+C
can copy - switch window and paste.Alternatively, if the windows are both open you can drag the Padlock icon (certainly with Firefox) to your field.