Tuple.append
You're seeing just the function
append, go back to Tuple module for more information.
Specs
Inserts an element at the end of a tuple.
Returns a new tuple with the element appended at the end, and contains
the elements in tuple followed by value as the last element.
Inlined by the compiler.
Examples
iex> tuple = {:foo, :bar}
iex> Tuple.append(tuple, :baz)
{:foo, :bar, :baz}