Instead of the 2 lines I was expecting (one line in/one line out in the existing mechanical switch), I have 3. Two are backstabbed, one top and one bottom, while the third one is screwed on the side of the switch adjacent to the bottom, backstabbed wire (See attached picture). The rest of the wires, ground and neutral, are all in there.

Based on what I have learned so far, the 3^rd black line could be a lightfeed, and I am wondering if anyone in this forum had run into this configuration. If yes, I am interested if it is an issue or how to wire the HS200 to make it work.

Thanks for any input!