U-Label
A U-Label is a the representation of an Internationalized Domain Name that is displayed to the end-user. It is string of Unicode characters that is valid within the Internationalized Domain Names for Applications protocol and includes at least one non-ASCII character.
Example
The U-Label for .бг, the country code top-level domain for Bulgaria, contains the Unicode codepoints U+0431 (б) and U+0433 (г).