Facebook over IPv6

[Ryan Rawdon]

nova-dhcp-host111:~ ryan$ host www.facebook.com 2001:470:20::2
Using domain server:
Name: 2001:470:20::2
Address: 2001:470:20::2#53
Aliases: 

www.facebook.com has address 66.220.146.25
www.facebook.com has IPv6 address 2620:0:1cfe:face:b00c::b
nova-dhcp-host111:~ ryan$


So it looks like Hurricane Electric's resolvers for their tunnel users are able to provide IPv6 answers for facebook.com now.  Does anyone know if this is the result of a DNS whitelisting program Facebook is running (a la Google), a special arrangement with HE, or something else?  

If it is a whitelisting program, is there somewhere to submit an ASN or resolver for approval?  (some Googling turned nothing up)