[NoThisIsMe]

From the article

> What this code does is read an index file that contains the list of R packages from CRAN, and subsequently download the description files of the first 200 packages to the user home directory (which is actually a virtual filesystem in WebR [1]). > [1] https://docs.r-wasm.org/webr/latest/mounting.html

So I think it's a virtual filesystem in browser memory.