What is "js-gps -track" as class name in almost every button and element in Stack Overflow?

I was exploring stack over flow's HTML and CSS then I noticed that JavaScript-GPS-track class is almost in every element.

When user click on upvote button then it also have that class. Even on footer links.

So, What is it exactly? Does it locate user's location or does it locate user's IP address?

If it does locate, then why using onClick class name?

Image of one of the class:

Any answers would be much appreciated.