Footprint Type,Description,Reference
ipv4cidr,IPv4 CIDR address block,[RFC8006]
ipv6cidr,IPv6 CIDR address block,[RFC8006]
asn,Autonomous System Number (ASN),[RFC8006]
countrycode,ISO 3166-1 alpha-2 code,[RFC8006]
altopid,A list of PID names,"[RFC9241, Section 4]"
subdivisioncode,"ISO 3166-2 country subdivision code: alpha-2 country code, followed by a hyphen-minus and up to 3 characters from A-Z;0-9 as a code within the country",[RFC9388]
footprintunion,A combination of other footprint objects,[RFC9388]