Nota Bene is another text-based word processor from that era. It defaults to showing embedded formatting commands. The primary means of operation is via an integrated DOS-like command prompt.

Nota Bene although no longer text based still exists and is actively developed. Nota Bene used the XyWrite word processor engine. XyWrite was very popular in news rooms back in the day.

That's a description that also matches Arnor's Protext. The command window was the bottom half of the screen, and one embedded rulers and suchlike into the document text with ">" lines.

This is testing my memory but I think WordStar from the early to mid 80s had something similar. Codes all started with a ^ (again from memory) and their visibility could be toggled on and off.