I don’t know how one would know short of a leak if Facebook’s track_ip_addresses.php, but is there any sense of how IPv6 is being aggregated by trackers to trac

I don’t know how one would know short of a leak if Facebook’s track_ip_addresses.php, but is there any sense of how IPv6 is being aggregated by trackers to track identity? We have a /48 at home using IPv6 privacy extensions for the full address but that isn’t a useful component of a strategy if I’m being identified by the /48 rather than the full 128-bit address.