I get: $ desktop-file-validate mozilla-firefox-bin.desktop mozilla-firefox-bin.desktop: warning: value "Application;Network;" for key "Categories" in group "Desktop Entry" contains a deprecated value "Application" Simply drop "Application" from "Categories" and you will solve it :-) Reproducible: Always
Thanks for the report, a depreciated value is a long way from following the specs tho IMO. I have gone ahead and updated firefox-bin.desktop.