Tbh, I'd rather see more pages adopting humans.txt, as I care way more about people than tools. The format also contains a section specifically for listing tools used to build the site though, so it covers that use case too:
/* SITE */
Last update: YYYY/MM/DD
Standards: HTML5, CSS3,..
Components: Modernizr, jQuery, etc.
Software: Software used for the development
We're a place where coders share, stay up-to-date and grow their careers.
We strive for transparency and don't collect excess data.