For those who love literate programming and fortran, PPPL developed this in the 80's: https://w3.pppl.gov/~krommes/fweb.html and I believe it is still maintained.

I've been working with PPPL people 15+ years and have not seen a code that uses it. However I did once get caught by a crazy, brilliant but crazy, Russian at PPPL that yammered on to me about a Latex programming language, that sounded insane but that may have been the delivery, that may very well have been this project. I am sure it is dead.