A recolored and blown-out version of the original, here you can see a little more detail... My hand on the gun, and perhaps most weirdly, the light spot on the back of the gun, which is actually the port blast inside the slide peeking out. Fire, fire, everywhere.

Porting on a firearm reduces the tendency of the muzzle (The potentially dangerous end) to rise up after being fired, which allows for faster follow up shots. Unfortunately, the side effects are that firing from retention (with the gun held close in at your side) becomes slightly dicier, the gun is significantly louder, firing at night can disrupt your night vision and obscure your target, and the internals of the gun get quite a bit dirtier.