GNU MIG is the GNU distribution of the Mach 3.0 interface generator MIG, as maintained by the GNU Hurd developers for the GNU project.
You need this tool to compile the GNU Mach and GNU Hurd distributions, and to compile the GNU C library for the Hurd. Also, you will need it for other software in the GNU system that uses Mach-based inter-process communication.
GNU MIG is fully compatible with OSF MIG.
Like its predecessor, it can only generate C code, that has to be compiled and linked to client and server programs respectively (open issue mig).