Yeah, also for PDP-8s and PDP-11s, which were very popular at the time.
TECO-like editors are interesting to use:
Unlike line editors (like ex/ed/edlin, etc.), the edit position can be anywhere, not just at line boundaries. But there is no screen, so you really need a good imagination to keep track of this..
Also, they can edit files larger than can fit in the edit buffer, but not in the way this works on modern editors, where the editor manages everything. Instead, the editor makes one pass through the large file, copying it from input to output. You get to make changes along the way, in the part of it that fits in the edit buffer.
TECO has a page concept to help with this: you break your large file into pages separated with form feeds, and there are commands to retrieve the next page from the input file and write the old page to the output file. But I've seen TECO clones without the page concept on early micros.
Vestiges of this page concept remain in emacs to this day..