For the current, official specifications of MiniZinc and FlatZinc, refer to the Reference Manual (part of the MiniZinc Handbook).
This page contains archived versions of previous specifications of Zinc, MiniZinc and FlatZinc, as
well as the specification of the MiniZinc to FlatZinc translation.
Note that Zinc and MiniZinc are specified in a single document because
they have a lot of overlap.
Nonetheless, the parts that pertain to MiniZinc are clearly marked.