The mzlib^ signature is defined by:
(define-signature mzlib^ ((open mzlib:core^) (unit zmath@ : mzlib:zmath^) (unit print-convert@ : mzlib:print-convert^) (unit print-convert-hooks@ : mzlib:print-convert-hooks^) (unit date@ : mzlib:date^) (unit inflate@ : mzlib:inflate^)))
The mzlib@ unit implements this signature by linking the mzlib:core@ unit together with the non-[CORE] standard library units.