Subclause 6.1 [basic.pre] paragraph 7 specifies:

A variable is introduced by the declaration of a reference other than a non-static data member or of an object. The variable's name, if any, denotes the reference or object.

Does this mean that non-type template parameters of class type are variables? Better not.

Possible resolution (January, 2025) [SUPERSEDED]:

Change in 6.1 [basic.pre] paragraph 7 as follows:

A non-template-parameter declaration is a declaration that is not a type-parameter or parameter-declaration of a template-parameter. A variable is introduced by the non-template-parameter declaration of a reference other than a non-static data member or of an object. The variable's name, if any, denotes the reference or object.

Possible resolution (per CWG reflector review starting 2025-03-18):

Change in 6.1 [basic.pre] paragraph 7 as follows:

A variable is introduced by the declaration D of a reference other than a non-static data member or of an object, where D is not the parameter-declaration of a template-parameter. The variable's name, if any, denotes the reference or object.