Update readme

README.md

@@ -32,7 +32,7 @@ cargo build
 `trace.bin`: Execution trace of the Cairo program.
 `memory.bin`: Memory dump of the Cairo program execution.
 `proof.json`: The generated STARK proof.
-`pie.zip`: Cairo PIE (Program Independent Executable) that can be generated by running the program and can be used re run the file in standardised way without inputs.
+`pie.zip`: Cairo PIE (Program Independent Executable) that can be generated by running the program and can be used re run the file in standardised way without inputs. This is only kept for reference/debugging purposes and not used for proof generation.
 `cpu_air_prover_config.json`: Configuration file for the CPU AIR prover(stone-prover).
 `cpu_air_params.json`: Parameters file for the CPU AIR prover(stone-prover).