If you missed that MS released a Tech Preview on SP15 Managed OM SDK…
SharePoint 15 Technical Preview Interoperability API Documentation
‘SharePoint 15 Technical Preview Managed Object Model SDK: This compiled help (.chm) file contains reference topics focusing only on types and members that are called by other Microsoft applications. This reference does not document the full SharePoint 15 managed object model. That documentation will accompany a later release of SharePoint 15.’
Early release as it is, its still interesting…
Others on SP15:
SharePoint Joel:
So it begins… SharePoint 15 & Office 15 Wave of Products – Happy Days
Rincón de Héctor Calvarro
SharePoint 15 SDK CTP has been released (Only documentation)
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Here is a post which has few more details:
http://praveenbattula.blogspot.in/2012/06/sharepoint-15-what-is-new.html