Using the program analogy. Astra is looking at outputs of a program, and re-compiling it.

And this thread is kind of arguing over whether using Notepad is really programming, and others saying, Astra really used VSCode with some fancy plug-ins, so that isn't really programming.

The neutral network was originally produced by training it in the usual way. So the training data is the "source code" and back propagation / gradient descent optimiser is the "compiler". That's what the human used to produce the network.

The weights are analogous to the compiled machine code. The LLM bypassed the compiler and edited those directly.