It actually consisted of a pair of programs, TYPSET (which was basically a document editor), and RUNOFF (the output processor). RUNOFF had support for pagination and headers, as well as text justification. (TJ-2 appears to have been the earliest text justification system, but it did not have the other capabilities.)
RUNOFF is a direct predecessor of the runoff document formatting program of Multics, which in turn was the ancestor of the roff and nroff document formatting programs of Unix, and their descendants. It was also the ancestor of FORMAT for the IBM System/360, and of course indirectly for every computerized word processing system. The name is alleged to have come from the phrase at the time, I'll run off a copy.