Now this is odd. After completing some research on claims based solutions in .NET, found that different authors refer to different classes in .NET namespace when actually speaking on the same matter. Claim class (not to mention other Identity, Principal, Manager, Helper classes around) is defined in 3 different namespaces.
It is clear that WIF is separate add-on for .NET 3.5 and 4.0 and that it is rewritten and made part of core in 4.5. However it could really help to have clear directions on what class to use for new projects (so that port to 4.5 after could be easier). Does anybody else have more info on the subject?
1st link: http://msdn.microsoft.com/en-us/library/ms572956(v=vs.110) (System.IdentityModel.Claims namespace)
2nd: http://msdn.microsoft.com/en-us/library/microsoft.identitymodel.claims.claim.aspx (Microsoft.IdentityModel.Claims)
3rd: (System.Security.Claims.Claim)