C71 Rom for HP 71b ?

[Michael Fehlhammer]

Does anybody know what the 64k module "C71" is about?
The image is burnt into an eprom, one module of that kind currently is offered in an auction. A C language compiler maybe ?
Is there a manual available anywhere?

[Allen]

I wonder if this could be the same custom 64K HP71b EPROM mentioned on p.28 of the CHHU chronicles Vol 2, No. 5 (Sept 1985)??