Pbuf.Decoder.map_field

You're seeing just the function map_field, go back to Pbuf.Decoder module for more information.
Link to this function

map_field(kp, kt, kd, vp, vt, vd, name, acc, data)

Specs

map_field(
  byte(),
  atom(),
  any(),
  byte(),
  atom(),
  any(),
  atom(),
  Keyword.t(),
  binary()
) :: {Keyword.t(), binary()} | {:error, Pbuf.Decoder.Error.t()}