What happens in away.php (vk.com)?

Question

PHP

When you click on any of the links in the contact, the page with away.php is loaded first, and only then it is transferred to the desired site. On a computer, this is almost not noticeable at all, but on a phone (most likely due to poor performance or a weak connection), this page hangs for 3-5 seconds.
And then there was interest.
- What is going on there anyway?
- What functions does it perform?
- What is it used for?
I understand that no one can know for sure. But at least approximately, or "for what" :)

Answer 1

This was done in order to be able to prohibit users from leaving the link. It will come to their mind not to let anyone on ok.ru using the links and when you click on the link, the page "Oh, you can't go there" will appear.

Answer 2

I will also add that when you follow the link, away.php gets into the HTTP Referer, and not the VK page from which the transition was made.

Answer 3

I will add that this is also to ensure that (a lot of swearing) in the statistics of the link it was not visible exactly where this link is located.