How does my system know which browser is the default? Or indeed any default something application?
$ cat ~/.config/mimeapps.list
[Default Applications]
text/html=userapp-Iceweasel-EZC28X.desktop
..
[Added Associations]
application/octet-stream=emacs24.desktop;
application/x-virtualbox-vmdk=userapp-virtualbox-LJU14X.desktop;
text/html=iceweasel.desktop;userapp-Iceweasel-EZC28X.desktop;
..
The .desktop files correspond to one of the files you have under
.local/share/applications/, e.g. this one for Iceweasel:
$ ls ~/.local/share/applications/userapp-Iceweasel-EZC28X.desktop
