Reacher body mass documentation

[rgap]

Hi,
I'm changing reacher's body_mass (Reacher-v2) and I find its default mass values are [0., 0.03455752, 0.03455752, 0.00418879, 0.00305363].
Is there a documentation where I could find which ones belong to the rigid links?

[jkterry1]

PR #2762 is about to be merged, introducing V4 MuJoCo environments using new bindings and a dramatically newer version of the engine. If this issue still persists with the V4 ones, please create a new issue for it.