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)

https://github.com/nrnrnr/noweb/tree/master/contrib/partingr