In 2016 models the option is "Max Towing Package" which provides a maximum tow rating of 8500#. It includes 3:42 gearing, integrated Trailer Brake Controller ("JL1"), Automatic Rear Air Suspension, Larger Oil and Transmission Coolers ("KC4 and "KG4"), Heavier Duty Brakes ("JD9" includes 17" disc), "Z85" HD suspension package, and a true 2 speed transfer case in 4 wheel drive models.
The option is $450 in 2WD models and I believe is $750 in 4WD models.
All Tahoe/Yukon/Suburban/Yukon XL/Escalade/Escalade ESV come standard with a Frame mounted hitch/receiver and a 7 pin wiring system/plug.
I think most PPV models are standard with "Trailer Equipment Delete".
The RPO glove box sticker code for 3:42 is "GU6"...Positraction/Limited Slip is "G80"...if you see "GU4" it's a 3:08. The code for HD Trailering Package is "NHT"...."Trailering Equipment, Heavy-Duty" is Z82. My 2016 Yukon with "Max Tow" has GU6, G80, NHT and Z82, JD9, JL1, KC4, KG4, JL1, Z85.
Hope this is helpful.