For the type of a declaration, only [dcl.meaning.general] p6 has a brief statement, that is

Thus, (for each declarator) a declaration has the form

T D

where T is of the form attribute-specifier-seq_opt decl-specifier-seq and D is a declarator. Following is a recursive procedure for determining the type specified for the contained declarator-id by such a declaration.

First, the decl-specifier-seq determines a type. In a declaration

T D

the decl-specifier-seq T determines the type T.

decl-specifier-seq is a sequence of decl-specifiers, where decl-specifier is separated into nine kinds of specifiers. The current standard does not explicitly specify which specifiers contribute to the type of declarations. Although, the text "type" in defining-type-specifier may hint that they designate the type. I think we may narrow the scope of specifiers in provision [dcl.meaning.general] p6, which may be that

In a declaration

T D

Except otherwise specified, the defining-type-specifiers in the decl-specifier-seq determine the declaration's type.

For instance, the exception is constexpr specifier, when it is declared in an object declaration, the effect on the type is the same as const, which is a special case specified in [dcl.constexpr] p10.