15.3.5.4 Imported syntactic bindings: variable macros

A syntactic binding representing an imported keyword binding with variable transformer has descriptor with format:

(global-macro! . (?library . ?loc))

where: ?library is a record of type library describing the library from which the macro is exported; ?loc is the storage location gensym containing the transformer function in its value field.

Syntactic bindings of this type are established by define-syntax, let-syntax and similar when the result of evaluating their right–hand side expression is the return value of a call to make-variable-transformer.