“A read only computer memory module containing medical information. This module details perception enhancements.”
The green memory module is a miscellaneous item in Fallout 2. It can be used to expand ACE's medical library.
The green module can be installed into ACE, in the Brotherhood's bunker in San Francisco. Doing so will allow you to use ACE to permanently increase your Perception by one.
This module can be found in Mariposa Military Base. It is on Level 3 of the base, in a lone locker in the first room of the main corridor that you come across, after leaving the elevator.