That’s the thing, there is no code in scribble-math which creates the katex folder. IIRC, there’s just https://github.com/jsmaniac/scribble-math/blob/main/dollar.rkt#L75 : (define-runtime-path katex-dir "katex") I think there is something in Scribble itself (not scribble-math) which takes care of copying the folder.

I believe that if you have a multi-document project, with a main.scrbl which uses https://docs.racket-lang.org/scribble/base.html#%28form._%28%28lib._scribble%2Fbase..rkt%29._include-section%29%29\|include-section to include other documents, then there should be (I think) only one copy of katex and other dependencies.