PHP: Set private, protected, public in interface?

Question

when I look through GitHub most projects define methods in the interface this way:

interface ExampleInterface
{
    function getId();
}

my question now is why it is bad style to define the method visability in the Interface:

interface ExampleInterface
{
    public function getId();
}

It makes the interface more strict but isn't that whats an interface used for?

Answer 1

what is the point of a private function in an interface? declaring public is redundant.

from TFM:

All methods declared in an interface must be public, this is the nature of an interface.

http://php.net/manual/en/language.oop5.interfaces.php