Bullet Physics version on Cocos 3.15.1?

This is my first question ever here. Glad to join this awesome community.

I’m trying to find out what’s the Bullet Physics version integrated in Cocos 2D-X 3.15.1. I know that the latest version of Bullets is 2.86 but, I’ve been looking in the changelog, and I can’t find a single reference to Bullet.
I need to know this int order to look for the right documentation.
Does anyone knows?

I need to know,too.