Annex A (informative) Grammar summary [gram]

A.7 Declarations [gram.dcl]

storage-class-specifier:
static
thread_local
extern
mutable
cv-qualifier:
const
volatile
enum-key:
enum
enum class
enum struct
alignment-specifier:
alignas ( type-id ... )
alignas ( constant-expression ... )
balanced-token:
( balanced-token-seq )
[ balanced-token-seq ]
{ balanced-token-seq }
any token other than a parenthesis, a bracket, or a brace