Despite being 32-bit, NT is able to run command interpreters under what it called NT Virtual DOS Machines (NTVDMs).

A look at the Mail application, which appears to use local "postoffices" that you are intended to share with others as a file.

Schedule+ uses the same "postoffices" as Mail, and is designed to allow you to share calendar and event scheduling information. Unfortunately apparently it has a Y2020 bug...

The help subsystem appears to look different but is otherwise functionally the same as 3.1.

Most of the applications in NT 3.1 have been re-written to be 32-bit, but are otherwise the same as the 16-bit Windows 3.1 applications. A few 16-bit applications still exist and are run in a compatibility layer.