That’s a great find, I wasn’t finding anything that close to legible as in easy to understand or at least close to there. I personally don’t understand it very well though I did managed to replicate some audacity functions at a elemental level, and echo is very much similar at a basic level. I’ll have a look at those in hope of finding something that’s easy to translate.
https://www.musicdsp.org/en/latest/Effects/42-soft-saturation.html
I found this. That seem very legible and understandable.