Well looks like somebody's been busy

If it supports diagnostic session 85 (ECU programming session) then it is likely that the firmware can be flashed using service 34, 35,, 36 and 37. Request Upload and Transfer Data, as well as possibly service 23 direct memory read.

Module obviously doesn't support that diagnostic session, likely it only supports mode 10 81, standard diagnostic session, 85 will definetly not be supported. Just skip starting a diagnostic session and go straight onto the service 2F request.

Nah this one not open source. Making it open source is giving away too much hard work.

You could (maybe);use DNspy if you really wanted to look at the source code.

If anything it would be done via traditional diagnostic services, so unlocking the module, request download, transfer data. It won't be anything like this because this is module manufacturer specific protocols and they were manufactured by different companies.

If you wanna message me on Facebook I can take a look at it remotely for you

Yeah what makes you think I care

I've made the Spanish Oak Flash Tool which can read and write a binary file from the FG PCM. https://testerpresent.com.au/software.html