Smartthings doesn’t expose anything, because no Smartthings Hubs are a “matter bridge.”
Smartthings only integrates with matter one way in. Not out.
There was one interview one time when one Samsung executive said they would consider bridge functionality sometime in the future, but no one else has ever said that. They’ve always said the hubs would not be matter bridges.
I just discussed this earlier today in another post, so take a look at that:
Nanoleaf Essentials won't connect to Smartthings - #13 by JDRoberts
Also, for a much more detailed discussion of how smartthings integrates with matter, as well as what other platforms are doing, see the following thread:
Matter - smart home connectivity standard (formerly Project CHIP)