What is the explanation for PHP's operator
It's the modulus operator, which gives the integer remainder of a division e.g.
7 / 2 = 3.5 // 3 remainder 1 7 % 2 = 1 // the remainder
Obvious real world example is working out whether a number is odd or even
if (($n % 2) == 0) the number is even, else it's odd... useful when you want to show alternate rows in a table in different colours