Huh - I didn't know that existed. Its not supported in firefox or IE11 though - and probably will never be.
(IE11 probably isn't super relevant now - but it was almost certainly more relevant when that tracking code was written. You could use feature detection - but its much easier to just use their hacky javascript everywhere instead.)
https://developer.mozilla.org/en-US/docs/Web/API/HTMLAnchorE...
https://caniuse.com/ping