How to disable Ctrl+Shift+C in Firefox
Solution 1:
I don't think we can anymore. Even through about:config you can set it to false but it still opens the developer console. There is 1 option that is guaranteed to work but it is not the nicest of methods: change the source and compile firefox. File ...
./devtools/startup/locales/en-US/key-shortcuts.properties
has an ...
inspector.commandkey=C
Change that to something else and recompile firefox.