Will Physx 2.8.x open source?

In 2.8.x 3.x physx havent some feature,e.g. RackAndPinion and CogWheel constraints .
if open source,developers can add it themself.

PhysX in proprietary to Nvidia, and is not open source. However, you the source can be licensed for a fee from Nvidia, in which case I think you are free to modify it to your hearts content.