In this directory you can find what I believe to be a perhaps early version of NB. The s2 tape has binaries size and fc that are neither machine code nor threaded B code. Instead we see a threaded code for a C-like language that supports byte and word types.

According to dmr's history of the C language NB had a machine code generator and ken told me (by email) that dmr's work on the code generator started on the Honeywell mainframe and that NB was always in machine code.

Whatever this is, it is something no longer B but not quite C yet.

nbrt0.s is a tiny bit of runtime that calls main.

nbilib.s is the threaded code implementation, names are mine.