You'll find here a description of the ML3.1 Porsche 911 3.2 maps.
ml31.zip contains the bins, disassembled versions and map listing of the bins:

• Carrera-1985-2732.bin : no cat 1984-1986 911 3.2
• Carrera32-1989.bin : cat 1989 911 3.2

The 1985 code was based on a PROM 8051 chip, the first 4K bytes of the code were hidden inside the chip. In order to understand the hidden code I've used the 1989 EPROM which contains the whole code, even if the code is likely slightly different from the PROM's one.
Then I compared the maps from both ECUs and saw that first 38 maps were identical. Some of farther maps are identical too.

• 1060 - 109B : map descriptors
• 10E0 - 110F : AFM transfert function
• 1110 - 117F : varius byte parameters
• 1180 - xxxx : map directory (the number of maps is different)

The Carrera32-1989.txt file contains a plain description of the code variables (parameters) as defined in the 8051 SRAM.
The Carrera-1985-2732.cfg is a configuration file of my EPROM editing tool. It's not very hard to understand.