Does anyone know the creators of cache?

There are three members listed on the famous map, "cache" I wonder what kind of $$ they got for this map, considering it is played everyday thousands of times, among thousands of people.

FMPONE
Volcano
penE

https://imgur.com/a/ZE6Yy

I would imagine they were paid a small flat rate by volvo for work on the map, but you can never be for sure as skins that are accepted from the community can make their creators thousands of dollars depending on their popularity.