SPWeb.Configuration property
SharePoint 2013
Gets either the identifier (ID) of the site definition configuration that was used to create the site, or the ID of the site definition configuration from which the site template used to create the site was derived.
Assembly: Microsoft.SharePoint (in Microsoft.SharePoint.dll)
Property value
Type: System.Int16A 16-bit integer that indicates the ID of the configuration. This value corresponds to the ID attribute of the Configuration element in Collaborative Application Markup Language (CAML).