Expose the full filesystem API Use it to check the directory structure and file contents >> Module.FS.root // represents the root path Object { contents: { dev: Object { id: 5, name: "dev", mode: 16895, … } home: Object { id: 3, name: "home", mode: 16895, … } proc: Object { id: 13, name: "proc", mode: 16895, … } tmp: Object { id: 2, name: "tmp", mode: 16895, … } wasmfiles: Object { id: 17, name: "wasmfiles", mode: 16895, … } } // a bunch more fields: like parent: {…}, mount: {…}, mounted: null, id: 1, etc. } When I did this to the actual code I was debugging, I found all of the virtual files, instead of containing numeric data, instead started with <!DOCTYPE html> and continued into Website created with create-react-app .