What are Dsg IHM objects?

[easternbun]

Open CASCADE Technology: DsgPrs Class Reference

I am browesing through the documents and found DsgPrs package saying it is used for Dsg IHM objects. I have no idea what it is.

 

[Quaoar]

I bet IHM stands for GUI in French and this whole package seems to be related to AIS visualization. It looks a little artifact-ish, maybe a relic from Euclid or something. I have never used this one and, to be honest, have never even come across it.