They got them before the restrictions took place. The other letter domain is:
http://i.net
The two letter ones I cant remember if they all get placed on reserve or only the ones that match foreign TLDs. Regardless that was the reason behind reserved two letter ones. They
are two similar to foreign TLDs.
domain.com.sa
Is how Saudi arabia uses TLD for example.
domain.sa.com
might confuse people..
Regardless if you already owned it you can grandfather it forever
There was another single character dot com that somebody allowed to expire making it reserved where nobody can obtain it. Or maybe I imagined that
