[zadikian]

Do they own such an address, as in, a packet sent by someone on another ISP to that address will actually reach my ISP's router over v6? Not talking about translations that use v4. If they do, I've never seen them actually give it to me.

[tardedmeme]

Yes, they can just put your 32-bit IPv4 address after their 32-bit prefix, and that gives you a /64 as is standard. If they want to. But what's the advantage?