was uhual trailer that did probably have the brakes, doubt I had the controller in that tahoe, i think the 'tow package' is just the electrical for lights and the button to keep it out of overdrive? you have to add those brake controllers separate I think?
the trailer almost had to have trailer brakes, i dont know if ive seen a car trailer without them.
and yeah tow package is probably the receive, trailer light wiring, maybe a trans and oil cooler and the button for improved shifting for trailering.
some trucks have the brake controllers built in, others you have to add. for my truck it was just a plug in harness from amazon for the controller I got... like 3 minute install.