RegionalInternet Registries (RIRs) and Domain Name Registries (DNRs) havehistorically maintained a lookup service to permit public access to someportion of the registry database. Most registries offer the servicevia the WHOIS protocol [RFC3912], with additionalservices beingoffered via World Wide Web pages, bulk downloads, and other services,such as Routing Policy Specification Language (RPSL) [RFC2622]. Thisdocument records an inventory of registry data objects tofacilitatediscussions of registration data objects. The RegistrationData Access Protocol (RDAP) ([RFC7480], [RFC7482], [RFC7483], and [RFC7484]) was developed using this inventoryas input.=> Some data elements were not supported by allRIRs, andsome were given different labels by different RIRs. Also, there wereidentical labels used for different data elements by different RIRs. o All ofthe 124 domain registries have the object names in their responses,although they are in various formats. o Of the118 WHOIS services contacted, 65 registries show their registrantcontact. About half of the registries (60 registries) supportadmin contact information. There are 47 registries, which is about one third of thetotal number, that have technical and billingcontact information. Only seven of the 124 registries give their abuse email ina "remarks" section. No explicit abuse contact information isprovided. o There are mainly twopresentation formats. One is key-value; the other is data block format. Most of thedomain-related WHOIS information is included in the top 10 data elements.Other information like name server and registrar name is also supportedby most registries. Nathalie Coupet