They check absolutely nothing and charge absolutely nothing 
Just kidding.. they will jack up your car and check it from underneath especially the bolts/screws. I myself hot underneath as well and checked everything myself as well...
In my case they also drove the car for 10 mins, checked ABS, checked fuel average in various modes used trip settings and upon reaching back at dealership took pics of MID's fuel efficiency screen.
They also cleaned the Cabin AC filter. Checked battery water, Air filter, Engine oil etc.
They also reved up the car in sports mode to assess acceleration. Upon asking they said that some units have fuel pump issue and hence they have specific instructions to do all this routine and take pics of the MID record and send it to IMC headquarters along with car details (Chasis/Engine number)
All in all it took about an hour with about 5 mons of waiting as I went early.. just after 9 am when they open up.
At the end they gave a green signal that everything is as it should be. 
The odd thing was that they repeatedly stressed changing first engine oil at 3000km and then every 5000km. Couldn't convince me though for a good reason for doing so...
Also despite techs saying that everything is fine just when I was about to leave the owner came and instantly suggested a tuning saying that it will do wonders to the average and I will get 20km/L...the techs looked surprised but told me to go as there is no need for tuning as soon as he left 
