Proposed resolution (approved by CWG 2025-12-05):

1. Change in 5.5 [lex.pptoken] paragraph 2 as follows:

   Each preprocessing token that is converted to a token (5.10 [lex.token]) shall have the lexical form of a keyword, an identifier, a literal, a header name, or an operator or punctuator.

2. Change in 5.10 [lex.token] as follows:

     token:
        identifier
        keyword
        literal
        header-name
        operator-or-punctuator
   

   There are five six kinds of tokens: identifiers, keywords, literals [ Footnote: ... ], header names, operators, and other separators. ...

(From submission #812.)

Consider:

  import "myheader.h";

The (phase 7) grammar module-import-declaration (10.3 [module.import]) expects a header-name, but that is not a valid token per 5.10 [lex.token].