I think you answered your own question. Keybinder is obsolete, the Developer left this note on his site in the last update notes :

• SORRY GUYS, BUT I'M AFRAID THIS IS THE END OF THE LINE.

+I wanted to release a last update to address a couple bugs, and mkz's locale but I'm afraid this will be the last update to Keybinder. Mozilla's self-destruct course wth Firefox (coupled with not even having adopted all WebExtensions APIs yet) makes this addon impossible to maintain (and sadly, soon to cease working at all). Already many commands will not work (especially new ones) as XUL is being deprecated, and XUL keysets was the foundation this add-on relied on.

Please Copy/Paste keybinder in to the search box in the below URL :

• https://addons.mozilla.org/en-US/firefox/extensions/

To see if you can find a Alternative or 2

No idea why it still shows what you set up, Or where that information is stored or how to remove it. Suggest Contact Keybinder Support Email :

• g.litenstein@gmail.com

Please let us know if this solved your issue or if need further assistance.

Thanks. I can't find an alternative... i really love firefox but i think it's crazy i've to spend all this time to just change 2 keys... if anyone know a working shortcut changer, please advise me.

I've tried Shortkeys but it doesn't fit my needs as shortcuts don't work in some area of firefox but just inside the webpage...

btw i've solved...

i've downloaded a firefox clone (waterfox) and there keybinder is still updated and i can work like in the past! awesome.

thanks to a friend of mine that advised me that :)