IDN Repository Procedures

The Repository of IDN Practices was created to support the development of the internationalized domain names (IDNs) by promoting the sharing of registry IDN policies. The policies are referred to as “Label Generation Rulesets” (LGRs), and historically as “IDN tables” or “variant tables.”
Specifically, as described in the Guidelines for the Implementation of Internationalized Domain Names:
We do not maintain the content of the data and hence are not responsible for its accuracy. The sole purpose of the repository is to publish LGRs that have been verified as coming from representatives of domain registries. Registries that implement IDN support are strongly encouraged to use this repository, and some may be contractually required to do so by ICANN.
LGRs should be listed in one of the following formats:
An LGR must contain the following elements in its header:
Bear in mind that the main purpose of this repository is to encourage re-use and analysis. As such, we recommend against submitting data in other formats unless it is not possible to represent the LGR using these available standards.
All delegated TLD registries can apply to register an LGR or submit an update to an existing LGR. Deprecated LGRs will be archived and marked as historical.
Service requests should be submitted to ICANN via the appropriate Naming Services portal. For more information, see IDN service requests.
Upon submission, within five days either:
LGRs may be revised according to the same process (i.e. request to idn-tables@iana.org followed by confirmation request to Administrative Contact). Updated LGRs must have a version number that is distinct from the current or previously posted version of the LGR. Updates should be accompanied by a description of the reason(s) for the request.
When constructing Label Generation Rulesets (LGRs), the languages and scripts the ruleset covers need to be specified. This is a list of common languages and scripts to aid in the classification process. For less common classifications, refer to the IANA Language Subtag Registry and RFC 5646.
For special cases there may be a need to list entries without a specific language or script classification. In such cases use und.
Note that we are unable to accept registrations for languages and script codes that are not recognized in the Language Subtag Registry.
As language names and country names are often similar, if not identical, there is often confusion between the two. Be careful not to accidentally use a country code when you intend to use a language code. Common errors we see include "kr" instead of "ko" for Korean, "jp" instead of "ja" for Japanese, and "dk" instead of "da" for Danish.
Country codes may be used, however, as geographic designators (which appear in upper case in language tags). For example, "ja-JP" means "Japanese as used in Japan," and "zh-TW" means "Chinese as used in Taiwan." Use script tags ("Hant," "Hans," etc.) to denote distinctions between writing systems.
The IANA functions coordinate the Internet’s globally unique identifiers, and are provided by Public Technical Identifiers, an affiliate of ICANN.