Never seen this one before.
I called this one out to have the Black Stove Shop professionals to inspect for proper installation. I believe the wood stove and the furnace were sharing the same flue.
The black hole; push those ashes in.
Besides the leaky valve, look close to the rear and you see the clean out door for the furnace flue. I only weigh 168 lb.'s and could barely squeeze behind there to open it up and when I did, it just emptied to the floor. That cleanout was for the furnace only.