Its a token for a specific class (i.e. token for sith warrior, token for sith inquisitor). There are 4 tokens in total for each of the 4 classes. Last boss have a chance to drop one of the four tokens.
The token(s) are then exchanged at the Tionese/Columi/Rakasa vendors on the Imperial Fleet (inner side of Supplies Quarter, if I recall correctly... although I frequently get lost, but I am sure someone will correct me if I am inaccurate). Many items can be exchanged either for 1 specific token _or_ lots of Commendations (and/or Crystals), but some will only drop as a token from the FP/OPS bosses.