clenbuterol isn’t a steroid...it’s a bronchodilator. It would theoretically allow him to breathe easier. It is popular with body builders as a fat burner...but I can’t see a tour cyclist needing it for that in the midst of the race.
There have been instances of clenbuterol contamination in food...beef and pork farmers will feed it to their animals to keep tham from getting too fat.
Ok, now I can see that as a possibility.