map -package:containers -package:foldl -package:incipit-base -package:base-compat -package:basement -package:aeson -is:exact -package:monoidal-containers -package:amazonka-core is:exact -package:hedgehog -package:invertible package:pipes

Apply a function to all values flowing downstream
map id = cat

map (g . f) = map f >-> map g