produkey, of MS-Office, Window (win 8.1 win 10)

ProduKey is a small utility that displays the ProductID and the CD-Key of
MS-Office, Windows (win xp win7 win 8 win 8.1 win 10), Exchange Server, and SQL Server installed on your computer.
You can view this information for your current running
operating system, or for another operating system/computer - by using
command-line options. This utility can be useful if you lost the product
key of your Windows/Office, and you want to reinstall it on your computer.