vBulletin Mods

I have seen a few sites that when you click on a link that takes you away from the forum (external link) that it displays a warning message. Anyone know where it is?

Redirecting To https://www.SomeDomain.com/Blah/Blah

Warning! The intended destination is not part of MyDomain.com.

If you do not recognise https://www.SomeDomain.com/Blah/Blah or do not trust the person who gave you this link, close this tab or click the Back button in your browser.

I understand the risk. Proceed anyway.