What is the tag @-ms-viewport in twitter-bootstrap?

Question

In my Twitter Bootstrap (Responsive) file, version 2.2.2, there is a tag

@-ms-viewport { 
    width: device-width 
}

I have seen @media and other @s. But there is no documentation for @-ms-viewport. Is it related to Microsoft or IE? Why is it the first style declaration?

Answer 1

You can read more about it here:

@-ms-viewport rule (Internet Explorer)

Specifies properties that describe the viewport.