It is simply an ‘unzipper’ for the files contained in an msi. I use it extensively to extract driver files (the inf and such) from stupid dell/hp/etc provided ‘installers’ so that I can make plug and play find them properly. I hope you get notified about this, or that you already know about it, because a simple ‘unzip it all into a subfolder’ method is much quicker for finding out what is in the msi.