This package generate a initramfs image that will try to mount the users filesystem, set on the root= flag on Linux command line. If it fails to do so, it boots to a Node.js REPL prompt using an on-memory root filesystem.

Since /usr/bin/env is also a Node.js script, to use less memory and boot faster it's checking that the script to be run is already a Node.js script and if so, it require()s it and exec it directly to re-use the current Node.js instance. This has the drawback that Python-inspired tricks like !module.parent or require.main === module will not work anymore. A better alternative and currently more widely used when a package can be used both as a library and as an executable is to define the executable at an independent script file and use the package.json main and bin entries.