The article describes the reverse engineering of the M4 Apple Neural Engine, a graph execution engine that executes neural network graphs as one atomic operation. The authors bypassed CoreML and talked directly to the hardware, discovering how to compile and execute programs on the ANE without CoreML. They also measured the true peak performance of the ANE, finding it to be different from Apple's claimed 38 TOPS. The authors used a combination of techniques, including class discovery, method swizzling, and binary analysis, to understand the ANE's software stack and hardware capabilities.