Hi @AlexK ,
I believe to remember that some days ago I was opening this /at least the main page / on github when I was searching for specific information. So I believe that this link was active for not so long time. I am not sure who is the owner but if this is hosting by R&D team I will ask there if there possibly someone have information about the current status.
I am not sure but I believe that the information what you are looking for on the mentioned link and related to information provided in the PTC Help:
Root link Use Case: 3D-Guided Service Instructions
3D-Guided Service Instructions 101: Use Attributes in Creo Illustrate
and further links in the chapter Get Started
The 3D-Guided Service Instructions use case will walk you through the following sections:
Additionally I think there is also another links on Github: --->
StudioExamples
and
I am not sure what all information's was in the deactivated link and if you can find in the links mentioned above the required informaiton. Please, let us know what information's your are looking for so I could check further or possibly some member of the community did have a backup of this information. Thanks BR.