This is the stand-alone Object Model Installer for TFS 2010 (Sp1). This may be used for developing applications that integrate with TFS 2010.
In other words instead of installing Team Explorer to start develop applications to integrate with TFS2010, here is the small set of DLLs that is needed to do the job.
Download from here: Team Foundation Server 2010 SP1 Object Model Installer
You can find more information about it in Buck Hodges Blog