The actual binary (vim.com in this case) is also a valid zip file, which it can read and write as a private virtual mount point. /zip refers to files inside the

The actual binary (vim.com in this case) is also a valid zip file, which it can read and write as a private virtual mount point. /zip refers to files inside the binary, inside the zip file. Redbean web server (by the author of Cosmopolitan, Justine.lol) also uses this method to store its web root.