There are various schemes for mapping IPv4 addresses in the IPv6 address space, for example [::ffff:127.0.0.1] [64:ff9b::127.0.0.1] https://en.wikipedia.org/

There are various schemes for mapping IPv4 addresses in the IPv6 address space, for example [::ffff:127.0.0.1] [64:ff9b::127.0.0.1] https://en.wikipedia.org/wiki/IPv6_address#Special_addresses https://en.wikipedia.org/wiki/IPv6_address#Special_addresses