Enum.reverse

You're seeing just the function reverse, go back to Enum module for more information.

reverse(enumerable)

reverse(t()) :: list()

Returns a list of elements in enumerable in reverse order.

iex> Enum.reverse([1, 2, 3])
[3, 2, 1]

reverse(t(), t()) :: list()

Reverses the elements in enumerable, appends the tail, and returns it as a list.

This is an optimization for enumerable |> Enum.reverse() |> Enum.concat(tail).

iex> Enum.reverse([1, 2, 3], [4, 5, 6])
[3, 2, 1, 4, 5, 6]