Kernel.is_bitstring

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

is_bitstring(term)

is_bitstring(term()) :: boolean()

Returns true if term is a bitstring (including a binary); otherwise returns false.

Allowed in guard tests. Inlined by the compiler.

iex> is_bitstring("foo")
true
iex> is_bitstring(<<1::3>>)
true