Find non-required files in your source tree. For big browserify project, this can turn up orphaned files.
npm install -g orphanarium
Point browserify at your entry point and run it with --deps to make it
output dependency paths. Orphanarium takes a single argument, the root
directory of files it should expect to be included.
browserify --deps src/index.jsx | orphanarium src
The utility outputs the full paths of non-included files, line by line.