Did exactly what I needed it to do: Ctrl+I is used to invoke italics in many online email and text editors, but Firefox inexplicably has that key combination set to open Page Info.

It did what I wanted most, to use Alt+Enter to open Full Screen, though I can't toggle Full Screen with the same combination...
Also, it would be a good idea to instruct somewhere how one can choose a bookmarklet to assign to a shortcut; I am not sure clicking

ok so weird thing that might be throughing people off is you type out the key,not press it, to set the shortcut. Also disabling 'alt' even in in the context of a page as far as highlighted text doesnt work. oddly though, remapping it to something like open new tab does.

doesn't work

Firefox 94, it works. Shortcuts seem to only work in tabs that were opened after you saved the preference. So, if the extension doesn't appear to work, restart the browser and you should be good to go!

I use this to disable Option+Home, which immediately navigates "home" (blank tab) and loses any filled-in form data on the page. Was bumping that key combo all the time because the keys are adjacent on my Kinesis!

Too many permissions for a shortcut key addon

Only thing that works

doesnt work at all :/

It's dead - I wanted to match the shortcut for the sidebar to my 'normal' system sidebar shortcut, but I can't.

A little cumbersome to set up (e.g. I forgot to press the "Save shortcuts" button and thought it wasn't working), but after it's configured, it works perfectly! I finally was able to disable Firefox's bookmarks sidebar shortcut (Ctrl+B) which I activate by mistake all the time when trying to paste something (Ctrl+V).

There is a typo "chortcut" on the download page.

It definitely works on Firefox 90 (the latest). Make sure you go to the GitHub page (linked in the add-on's description) and click the "Wiki" tab near the top to make sure you're setting it up right.