Why singleton tag doesn't requires a closing tag?

Question

In html we many tags that not required to be closed like <img>,<br>.

can anyone explain?

Answer 1

Basically Singleton Used to Require Closing Tags but after updation of VERSION it doesn't need it anymore

Answer 2

it's a matter of definition first of all. a possible explanation is that they are already closed.
but most browsers will get the idea even if you include a '/'.