It allows to upload extracted game data via ftp to avoid requiring the double the size at the vita or even having to decompress it in the computer. It decompresses and uploads to psvita directly on the fly.
You can get the source code + JAR binary here: https://github.com/soywiz/vitaorganizer
Last version with VitaShell >= 0.92 is capable of installing games directly without any user interaction via ftp



