Macaroon.add_third_party_caveat

You're seeing just the function add_third_party_caveat, go back to Macaroon module for more information.
Link to this function

add_third_party_caveat(macaroon, location, caveat_id, caveat_key, nonce \\ nil)

Specs

add_third_party_caveat(
  Macaroon.Types.Macaroon.t(),
  binary(),
  binary(),
  binary(),
  false | nil | binary()
) :: Macaroon.Types.Macaroon.t()

Add a third-party caveat to a Macaroon provided a location, caveat_id, and secret caveat_key