A behavioral circuitry matrix was a droid part. In 3 ABY, after the droid engineer RB-919 rebuilt the assassin droid IG-88 on the orders of Deva Lompop and Crimson Dawn, RB-919 placed a chip into IG-88's behavioral circuitry matrix that contained the details of his upcoming mission, to acquire the carbonite-frozen body of Han Solo from Boba Fett.