Overview

This document specifies an integrated collection of 26 String Similarity Evaluation (SSE) data files, merged with a file derived from Root Zone LGR Common file (See [RZ-LGR-6]) plus a template document providing this description, for a total of 28 contributing files.

This file contains a global superset of all confusables mappings plus all Root Zone variants, combined with the full repertoire of the Root Zone LGR as used for similarity calculation. As such, this file can be used to calculate an Index Label from any valid label (or valid variant). If the index labels for two labels are disjoint, they are neither variants nor confusables.

If, on the other hand, the index labels coincide, further investigation is required. This process is described elsewhere. See also [SSE].

Any computations performed using this file must be limited to labels that are valid according to the relevant script LGR from [RZ-LGR-6].

File Format and Conventions

The format of this file follows [RFC 7940], with the following conventions:

• All code points and sequences are annotated with their respective script.
• Any item that is common to all Data Files (or a group of Data Files) is marked with a ⍟ in the comment. This ensures that the item is recognized as not specific to a single Data File and the name for it is not prefixed during integration.
• Any elements other than Repertoire or Confusables Sets are artifacts of merging the RZ-LGR and its variants.

Note while the file uses the same schema and data structures defined in [RFC 7940] it does not define a set of Label Generation Rules (LGR).

The XML version of this file is the normative specification, the HTML version is provided for ease of reading. It contains additional explanatory text and other information such as summary counts or descriptive data extracted from the Unicode Character Database.

Comments

Most comments from the contributing data files have been removed. A comment marked with ⍟ indicates an item explicitly shared among two or more Element Data Files, or an item required by integration.

Confusables

The confusables mappings in this Data File are based on the union of the confusables mappings from the 26 String Similarity Evaluation Data Files as well as the variant mappings from the Common file for Root Zone LGR-6 [RZ-LGR-6]. The data from these files has been integrated into this merged Common String Similarity Evaluation Data File.

Imposed Mappings. After computing the union, the confusable mappings are mechanically augmented, if needed, to ensure transitivity of the full set. Any mappings added as part of this are marked with a comment Imposed and have been given a distance category of "4". The assumption is that while they are formally required for transitivity, they may not represent actual similarity.

String Similarity Categories. The detailed categories from the String Similarity Evaluation Data files or the variant types from the Root Zone LGR have been merged, to allow for String Similarity Distance computation for pairs of labels within and across scripts. Where two Element Data files define the same mapping with different distance categories, the discrepancy is resolved by assuming the closer distance.

Sequences and Context Needed for Label Validation

The Common data file from [RZ-LGR-6] contains some definitions of sequences or context rules that are required for label validation but are immaterial for index label or distance computation. Where they interfere with the definition of confusables, they may have been commented out before merging the file. Likewise, some context rules on variants were reformulated equivalently to better support required contexts on confusables mappings.

References

In the listing of the repertoire, references starting at [0] refer to Unicode Standard versions in which the corresponding code points were initially encoded. References [102] and above correspond to the script- or language-specific Data Files that include the repertoire item. Repertoire items may have more than one reference.

In addition, the following references are cited in this document or they form a background document:

[Proposal-Devanagari]

Neo-Brahmi Generation Panel, “Proposal for a Devanagari Script Root Zone Label Generation Rule-Set (Data File)”, 22 April 2019, https://www.icann.org/en/system/files/files/proposal-devanagari-lgr-22apr19-en.pdf

[Proposal-Myanmar]

Myanmar Generation Panel, “Proposal for a Myanmar Script Root Zone Label Generation Rule-Set (Data File)”, 17 March 2022, https://www.icann.org/en/system/files/files/Proposal-Arabic-lgr-17mar22-en.pdf

[SSE]

String Similarity Evaluation Data for the New gTLD: Next Round, ICANN, 23 July 2026, https://www.icann.org/en/system/files/files/sse-data-overview-23jul26-en.pdf

[RFC 5891]

J. Klensin, “Internationalized Domain Names in Applications (IDNA): Protocol”, RFC 5891, August 2010, https://www.rfc-editor.org/info/rfc5891

[RFC 6365]

Hoffman, P. and J. Klensin, “Terminology Used in Internationalization in the IETF”, BCP 166, RFC 6365, DOI 10.17487/RFC6365, September 2011, https://www.rfc-editor.org/info/rfc6365

[RFC 7940]

Davies, K. and A. Freytag, “Representing Label Generation Rulesets Using XML”, RFC 7940, August 2016, https://www.rfc-editor.org/info/rfc7940

[RZ-LGR-6]

Integration Panel, “Root Zone Label Generation Rules (RZ-LGR-6)”, 23 September 2025 (XML), https://www.icann.org/sites/default/files/lgr/rz-lgr-6-common-23sep25-en.xml
non-normative HTML presentation: https://www.icann.org/sites/default/files/lgr/rz-lgr-6-common-23sep25-en.html
The actual RZ Common LGR file used in the computation of the SSE Common has been slightly modified.

[Unicode 16.0.0]

The Unicode Consortium. The Unicode Standard, Version 16.0.0, (South San Francisco: The Unicode Consortium, 2024. ISBN 978-1-936213-34-4) https://www.unicode.org/versions/Unicode16.0.0/

For details on references [0] and up and [101] and up, please refer to the Table of References below. Please also consult the String Similarity Evaluation Data files for the respective scripts.