Its the Microsoft Office 15 Technical Preview version, which Microsoft recently made available only to a select group of customers. The Office 15 Technical Preview doesn't appear to work well in a clean install configuration, but you can upgrade from an existing valid copy of Office 2010 Professional Plus easily enough.
It is logical to assume that it is somewhat unstable. However, even at the current stage of development we can see some improvements made to the functionality and appearance applications.
The assembly contains time bomb (will expire after a certain period of time). Period of operation has not been determined. Also, despite the type of publication Starter and typical installation mechanism (Click-to-Run), a part of the image are all available applications, namely:
Microsoft Access 15
Microsoft Excel 15
Microsoft InfoPath Designer 15
Microsoft InfoPath Filler 15
Microsoft Moorea 15
Microsoft OneNote 15
Microsoft Outlook 15
Microsoft PowerPoint 15
Microsoft Project 15
Microsoft Publisher 15
Microsoft SharePoint Workspace 15
Microsoft Visio 15
Microsoft Word 15 System Requirements
: Same as for Office 2010. Also works on Windows 8.