I updated the content to the latest markdown format.
Getting a clean binary from the actual cartridge I bought on ebay. I put a piece of tape over the cart interrupt. The first byte is 0x12, as one of my images shows. Maybe that image is correct? Let me run a checksum and see.
On the CoCo I got 787090 from C000 to DFFF. I wonder if the cartridge goes into the E000s. Surely not. But the cartridge does use A13 and A14. Hmmm. C000 to DFFF only needs A0-A12. I will have to take the cartridge apart.
The checksum of my binary matches 787090. I'm going to say they are the same.
Now for this above-E000 stuff.
I ran a loop. There is data up there. Without the cartridge, the loop prints 255s. With the cartridge there is stuff.
The stuff appears to go right up FF00 (E000-FEFF).
Ah ha! The pins on the cartridge connector go nowhere. I checked the "stuff". It is just a ghost of C000-DFFF. Good. The cartridge is standard 8K, and I have the binary.
I can't find any info on what happens when you finish the game. I guess I'll look at the code to find the answer.