27 Sep 2012
10 Jan 2014
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Not sure if this helps you out but if you log in to your Sitefinity account and where you download the installer and project manager there is a project called "SitefinityStsWebApp_6.3.5000.0.zip", the description is "Sitefinity STS Web Application is used for Single Sign On between several Sitefinity instances. For more information, check the Documentation."
I also poked around on Github and found this: https://github.com/Sitefinity/Sitefinity-External-STS-Integration