Been around for a long time indeed. I first learned literate programming in college at Tufts, from Norman Ramsey. He wrote noweb[1], an early implementation of Knuth's ideas.
One of my first software contributions was indexing and cross-references for noweb in plain TeX. I had thought it was completely lost to time and hard drives but it seems someone has actually kept it around! Bonkers.
(The username being `partingr` suggests it was some time late 92 to mid 95 whilst I was at cs.man.ac.uk)
I used something called nuweb for a class project back in the late 90's (an implementation of the "bully algorithm" in Java).
I don't remember why I selected nuweb, other than it worked with any language, but it looks like it was inspired by noweb. I had learned about literate programming from studying TeX.
[1]: https://en.wikipedia.org/wiki/Noweb