I've downloaded the User Guide and had a look at p63 - Surface Input Component. However, it only has one paragraph which says: "Accesses to the Surfaces attribute set from the connected Archicad project. Currently , this Input Component is available for only the CW Frame Settings and CW Panel Settings components".
In your screenshot though, you appear to have a different object settings node than what I get in GH.
I hope I read the sections correctly, you're screenshot above seems to cover all the relevant info with regards to my original query.
From what I understand, the Surface Input Component is only available for the Object Settings Node. Furthermore, it only works when utilizing an existing object (library part), not for creating new Objects. Also, it only works if you do some editing of the GDL code.
I'd add a wishlist item to make the Surface Input Component available for other nodes, but it's likely due to the complexity of the connection as to why it's not available now.
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