A new patent for the Nintendo Switch 2 has revealed new functionality with the joy-con controllers, and while Nintendo hasn't officially confirmed the functionality, the company did subtly showcase it in its most recent trailer for the Switch 2.
The new patent shows Nintendo has been exploring using its Joy-Con controllers like a computer mouse, which was briefly showcased in the above trailer with the Joy-Con's sliding around on their connector side. However, it wasn't touched on for the rest of the trailer and was left to ambiguity and speculation. But, the newly released patent provides more details on the proposed functionality, as the images included in the patent show the Joy-Con being held horizontally with both the SR and SL buttons facing downward, with a user's thumb placed on the joystick.
More specifically, an image shows the right index finger and middle finger placed over the R and ZR buttons, similar to the left and right buttons on a traditional mouse. This design has led to the assumption that an optical sensor within the joy-con is downward facing. The patent also includes the translation "mouse operation sensor" 28 times, according to The Verge.
It should be noted that patents aren't indicative of the features/hardware included in the final product, but given that Nintendo itself has alluded to this functionality being included, I believe Joy-Con's having some kind of mouse functionality is all but confirmed.

