Apparently NASCAR just switched over to this new system to fuel the cars. Each pit stop uses one of these canisters. Fuel goes in-air goes out. Minimal fuel spills.
While heading from the pits to the track each car had some sort of emblem from their main sponsor on the hood. These were removed before go time.
The pit crews def take their jobs extremely seriously. It was common to see the teams stretching, meditating, and getting into gametime mode.