Just tried Quake in mouse mode with my wife's Lenovo Legion Go

https://lemmy.world/post/31061622

Could someone explain the “mouse mode”? Is it at all different from the Steam Deck’s ability to map trackpads and thumbsticks as mouse inputs?
It turns the right-hand “joycon” (for lack of a better word) into a mouse for FPS games (or whatever else).
Is this done via a control on the “joycon” or on the main device? Seems like good functionality that would be straightforward to implement with other similar devices (and may have enough “prior art” examples to reduce patent trolling).
There’s a normal mouse sensor on the joycon