Depois de usar meu sistema por algum tempo, parece que um dos meus programas fez com que o arquivo fosse criado em ~ / .config / mimeapps.list
sudo find / -name "mimeapps.list"
cat ~/.config/mimeapps.list
[Added Associations]
image/jpeg=gimp.desktop;
text/x-java=eclipse_eclipse.desktop;
application/json=sublime_text.desktop;
application/rdf+xml=sublime_text.desktop;
text/x-python=sublime_text.desktop;
video/mp4=vlc.desktop;
application/octet-stream=org.gnome.Software.desktop;
application/pdf=evince.desktop;
text/html=org.gnome.gedit.desktop;
text/plain=firefox.desktop;
[Default Applications]
application/ppdf=FoxitReader.desktop
application/octet-stream=FoxitReader.desktop
application/pdf=FoxitReader.desktop