Universal Relay/Static region allocations

The region below :600:0:0:0 is referred to as the "static region", as opposed to the region above it for Transparent Happy Eyeballs.

Range (relative to ipv6_prefix)	Purpose of use
:0:0:0:0 -- :3ff:ffff:ffff:ffff	Private/local use
:5fe:0:0:0 -- :5fe:ffff:ffff:ffff	internally resolved to i-hx-XXXXX-YYYYY.u-relay.home.arpa where XXXXX is the upper 16 bits of the lower 48 bits in decimal, and YYYYY is the lower 32 bits in decimal; intended to be used in conjunction with groupsub_map. This region can also be used to facilitate NAT64 through other upstream interfaces using groupsub_map with ip_subst set to 0.0.0.0/0 and bind_addr or socks_server selecting the desired upstream interface.
:5ff:6464:0:0 -- :5ff:6464:ffff:ffff	NAT64; the ipv4only.arpa domain is statically configured to point to this region on the programmatic DNS server.
:5ff:7001:0:0 -- :5ff:7001:ffff:ffff	static allocations for domains in relay_map; see Universal Relay/Static maps
:5ff:7002:0:0 -- :5ff:7002:ffff:ffff	internally resolved to i-host-NNN.u-relay.home.arpa where NNN is the bottom 32 bits in hexadecimal -- the ultimate destination can still be configured using hosts_map, resolve_map, and/or domain_canonicalizer
:5ff:7003:0:0 -- :5ff:7003:ffff:ffff	internally resolved to i-hx-sXXXXX-YYYYY.u-relay.home.arpa where XXXXX is the upper 16 bits of the lower 32 bits in decimal, and YYYYY is the lower 16 bits in decimal; intended to be used in conjunction with groupsub_map