In PHP what does |= mean, That is pipe equals (not exclamation)

Question

|= is to | as += is to +; that is, $a |= $b; is the same as $a = $a | $b;. The | operator is the bitwise OR operator.

Or-Equals. Similar to saying $var += 2, or $var = $var + 2. In this case, it's $showPlayer = $showPlayer | isset....