[p1mrx]

If your address on ripe.net doesn't match any of your local interface addresses, then that's NAT (or perhaps a transparent proxy) by definition.

Well, in some environments, it's possible to bind() to an IP address that's not actually present on a local interface, but it's unlikely that your browser would support that.

[betaby]

On other side I can ping IPv6 address of the tethered laptop. And for tethered devices ripe reported IPv6 matches interface. Indeed, transparent proxy / media gateway could be the case for the phone itself.