[xaedes]

My observations: I rarely see it in computer science related papers. I often see it in biology / medicine papers (but I don't see lots of those papers)

If you wonder what 21 people do for one paper, they have mentioned it in the paper pdf (look for the scihub link here in the comments) on the last page: Only two people actually wrote the paper with input from a lot of others, supervised by yet another one.

[motajaxxer]

Lab experiments involve huge amount of support people who have to do really specific work for each experiment.