Thanks denman. I had not yet found a complete service manual.
Still, the oven floor removal instructions are:
"Remove the two screws holding rear of the oven bottom to liner tabs and lift the rear of the bottom up and slide it back."
This is what I've tried to do. The back of the panel will rotate upwards, but otherwise it won't move at all.
I will read through the manual thoroughly and see if there's something else going on, or what other ways I can get to the ignitor, but I'm trying not to take it apart more than I have to.
In the meantime, if anyone has encountered something like this before please let me know. Thanks. And thanks again denman.