The script is available for download from http://gallery.technet.microsoft.com/How-to-keep-an-unlicensed-4e115709. You can also use Microsoft Script Browser for Windows PowerShell ISE to download the sample with one button click from within your scripting environment.
This script is used to help administrators to keep an unlicensed account's mailbox address or contents.
When an account won't be used anymore, the license would be removed for this account. But the mailbox's address or contents should be kept for further reference.
You can find more All-In-One Script Framework script samples at https://aka.ms/onescriptingallery