I think they were using "#lang system" as a synecdoche[0] for "Racket's language support". Racket's USP is definitely that it's a platform for language design a

I think they were using "#lang system" as a synecdoche[0] for "Racket's language support". Racket's USP is definitely that it's a platform for language design and implementation[1]. On the other hand, I don't think it's a big deal they moved off of Racket. I actually think it's a success story that they were able to build on the platform and then move off. [0]https://en.wikipedia.org/wiki/Synecdoche https://en.wikipedia.org/wiki/Synecdoche [1]https://en.wikipedia.org/wiki/Racket_(programming_language) https://en.wikipedia.org/wiki/Racket_(programming_language)