Change Firefox tab-switching  keyboard  shortcut To move to the next tab in most browsers, you use ctrl+&#x21E5;.

Then, to close it, you have to reach over to &#x2318;+W.

I don't like switching modifier keys like that; I'd prefer to just use ctrl for both.
Is there a way to change the shortcuts so that both shortcuts use the control key? It would be great to switch this globally, but otherwise a solution for Firefox would be fine too.
This is the definitive answer. Here are two official FireFox add-ons (plugins) that let you modify or define your own keyboard commands and shortcuts.

Key config

My Keyboard Navigator