I'm on Windows 10, how can I switch tabs with Alt+[1-9] instead of Ctrl+[1-9]?
Look, in Windows I switch tabs with Alt+Tab, in any text editor that I use I switch tabs with Alt+[1-9] and every time I switch from Sublime Text (or whatever) to Firefox and I want just to rapidly switch to another tab I need to move my left thumb from Alt to Ctrl, which is very uncomfortable, first of all, annoying and time consuming. I NEED to remap the shortcuts to Alt+[1-9] instead of Ctrl+[1-9]. Please help, this is driving me insane.
That would be a Windows function not a FF problem. You need to look at your Keyboard configuration to redo the keyboard mapping. FF can't do this since Windows controls this function.
You don't get it. In Firefox you use Ctrl+[1-9] to switch tabs (on Windows at least, on Ubuntu it's Alt+[1-9] as it should be). I want to switch tabs with Alt+[1-9]. The equivalent question would be: How do I remap keyboard shortcuts in Firefox? Do you get it now?