“A read only computer memory module containing medical information. This module details Charisma enhancements.”
The blue memory module is a miscellaneous item in Fallout 2. It can be used to expand ACE's medical library.
The blue 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 Charisma by one.
This module can be found within a locker inside the Enclave base at Navarro. The row of lockers to look in are in the armory, which is in the underground level, next to the Quartermaster.