How Come All Dogs Have That Black Wart On Their Cheeks?

Does anybody know why all dogs have that black wart on their cheeks with the piece of hair coming out of it? What purpose does the wart on the cheek serve? I've noticed this wart on all dogs. And no, I'm not talking about this wart as being a medical condition on dogs because it's not. I've always wondered about this. Is there a name for this wart? If anybody knows the answer, please respond. I'd really appreciate it. Thanks. Take care.

This is a super weird question. It's not a black wart, it's the base of a hair follicle where the hair grows out. Sometimes it can feel like a lump. Dogs usually have multiples of these on each side of their face as well as under the chin. They're not warts at all.