- <p>Unicode escape sequences are permitted in an |IdentifierName|, where they contribute a single Unicode code point to the |IdentifierName|. The code point is expressed by the |CodePoint| of the |UnicodeEscapeSequence| (see <emu-xref href="#sec-literals-string-literals"></emu-xref>). The `\\` preceding the |UnicodeEscapeSequence| and the `u` and `{ }` code units, if they appear, do not contribute code points to the |IdentifierName|. A |UnicodeEscapeSequence| cannot be used to put a code point into an |IdentifierName| that would otherwise be illegal. In other words, if a `\\` |UnicodeEscapeSequence| sequence were replaced by the |SourceCharacter| it contributes, the result must still be a valid |IdentifierName| that has the exact same sequence of |SourceCharacter| elements as the original |IdentifierName|. All interpretations of |IdentifierName| within this specification are based upon their actual code points regardless of whether or not an escape sequence was used to contribute any particular code point.</p>
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