This is the source code to components of NetbootCD 6.4.1 that are not already included with CorePlus.
You can get Tiny Core source code at http://tinycorelinux.net/6.x/x86/release/src/ and http://tinycorelinux.net/6.x/x86/tcz/src/.
To actually build NetbootCD from a CorePlus ISO, go to https://github.com/IsaacSchemm/netbootcd