All key mapping data is saved in the form of its own custom profile, and it works just fine for assigning standalone keys as well as combo actions. The Xbox blog post notes that you can get four extra shortcuts if you map actions to keyboard keys, something that won’t be possible without the latest feature. This convenience is tied to the Xbox Elite Wireless Controller Series 2 paddles and the X1/X2 inlets on the Xbox Adaptive Controller.
Do keep in mind that a controller key can only be mapped in combination with one single modifier key. So, you can assign an action key to the entire “Ctrl + Shift + C” sequence, but trying to add an extra modifier to get a sequence such as “Ctrl + Alt + W + E” won’t work. Another aspect you need to remember is that the controller must be plugged in via a wire, or it must be hooked to the Xbox Wireless Adapter during the setup. Keyboard mapping over a wireless Bluetooth bridge isn’t allowed.