Programming language developed in DEC SRC in early '90s. Started as joint effort with Olivetti labs, it is now collection of few compilers with similar origin and varied runtime and extended features. Most authoritative site is http://www.modula3.org and it's good reference point.

HoNet developed it's own "flavor", HM3 (currently in version 1.1.0), based on pm3-1.1.15, updated for glibc changes through RedHat/Fedora history after pm3-1.1.15 is released, with native threading using NPTL and updated support for gdb 6.0. This is obsoleted as we've moved to Critical Mass Modula-3 (cm3).