I went back through my photos of the job.
I found the two screws that had me dismiss this.
And this one. It was a couple of years ago now. I recall wondering if it was possible but couldn't figure out how these two could be reached. They could be broken off but then the ducts would never meet up properly after.
The heater core can not be removed the same way. Well, it might be. If the pipes were cut (not with a saw but a pipe cutter), super carefully cleaned, and had an AN fitting installed onto it and a suitable braided hose flexible hose attached and mated to the pipes coming in. I know people used to do that all the time and its crazy.
The method of cutting the pipes and sticking a rubber hose on is rediculously dangerous. Super dangerous. If the hose lets go, the driver will be instantly burnt in nasty ways and a crash would be likely. Other people going about their business become involved and would also be harmed unnecessarily. Perhaps a well fitted AN and braided hose would be suitable?
The screw is hard to see here, but is just left of that tab on the floor.
*Of note, the after market Jayair evaporator did not come close to fitting. Bought genuine for the same price and It went straight in, no worries.