Positronic decompiler

From Memory Alpha, the free Star Trek reference.

A positronic decompiler is a program that breaks down the source code of the matrix in the positronic brain of a Soong-type android, allowing the existing code to be altered, essentially changing the behavior and abilities of the android.

Data's positronic decompiler features a "Type R" phase discriminator, while his brother Lore has a "Type L". (TNG: "Time's Arrow")