There is only one file type that uses the .WSPAK extension:
WebsitePanel Backup File
Backup file created by WebsitePanel, a portal application used for managing Windows Server applications such as IIS, SQL Server, Exchange, and Hyper-V; saves a backup of databases, settings, and other files on the server; can be used for migrating files to a new server; most often used by system administrators.
WSPAK files are saved in a compressed .ZIP format, so you can view their contents manually with a Zip utility. However, they are typically not decompressed and extracted manually.
NOTE: WebsitePanel only runs on Windows Server (i.e., not Windows Vista, 7, or 8).
Updated: October 9, 2012