All firefox addon can't use in https://addons.mozilla.org/.
It's a specification of firefox. I think it is for falsification of data.

> ctrl+shift+c opens developer console for me.

Now, firefox addon supports custom shortcut key. you can change the short cut from the addon short cut settings
like this
https://www.ghacks.net/2019/01/16/manage-firefox-add-ons-keyboard-shortcuts-on-aboutaddons/