The top-level domain (TLD) xn—45q11c is a Internationalized Domain Name (IDN) TLD and is encoded in the punycode format. Punycode is a type of encoding used to represent Unicode within the limited character subset of ASCII used for Internet host names.
In simpler terms, an IDN TLD is a domain name that contains at least one label that is displayed in software applications, in whole or in part, in a language-specific script or alphabet, such as Arabic, Chinese, Russian, Hindi or the Latin alphabet-based characters with diacritics, such as French.
The xn— prefix is what signals web browsers that the domain uses punycode encoding to represent Unicode characters. But the remainder that comes after the xn—, in this case 45q11c, represents a string of ASCII characters which map directly to a specific string of Unicode characters based on the Punycode encoding.
To decode the xn—45q11c back to the Unicode representation, we can use online Punycode decoders such as the Punycoder (https://www.punycoder.com/). Upon decoding xn—45q11c using this tool, we find that it represents “.商城” in Chinese characters or “.shop” in English. Hence, it provides the benefit that web addresses can be written in the user’s own language or script.
IDNs are important for maintaining cultural diversity on the web, especially as Internet penetration rises in non-English-speaking nations. They are fully supported by the Internet Corporation for Assigned Names and Numbers (ICANN), according to the “Internationalizing Domain Names in Applications (IDNA)” standards.
For more technical understanding regarding punycode, you can refer to the RFC 3492 – Punycode: A Bootstring encoding of Unicode for Internationalized Domain Names in Applications (IDNA). For the broader understanding of Internationalized Domain Names, you could refer to the ICANN’s guideline on IDN.
References:
1. “IDN Code Points Policy for the Root Zone”, ICANN, https://www.icann.org/resources/pages/idn-2012-02-25-en
2. Punycode, Wikipedia – https://en.wikipedia.org/wiki/Punycode
3. “RFC 3492 – What is Punycode”, RFC Editor, https://www.rfc-editor.org/rfc/rfc3492.txt
4. Internationalizing Domain Names in Applications (IDNA), ICANN, https://www.icann.org/resources/pages/idn-2012-02-25-en
5. “Punycode: A Bootstring encoding of Unicode for Internationalized Domain Names in Applications (IDNA)”, Faltstrom, P., Hoffman, P., Costello, A., (March 2003) https://datatracker.ietf.org/doc/html/rfc3492
