Firefox

I was being unclear; I meant the optional suggested keybinding would be bound to virtual keys for common actions.

The goal of that is to rebind common actions globally. Without this, you'd have to change each application's individual "copy" action to your preferred shortcut. You'd do so in the OS rather than the app but you'd still have to do it for each app individually.

Alternatively, there could be a set of pre-defined common actions that applications would simply use rather than defining their own action. I think that's what you mean.