I had a peek at the SDS because this is what's recommended for my 08 Trailblazer, it appears to be mostly PAO with some esters and a few other adititves.
Component CAS No. Amount
1-Decene homopolymer, hydrogenated 68037-01-4 10-80 %
1-Decene trimer, hydrogenated 68649-12-7 10-80 %
Hexanedioic acid, ditridecyl ester 16958-92-2 3–7%
Zinc and Zinc Compounds Proprietary <1 % Phosphonic acid,
dibutyl ester 1809-19-4 <1 %