Compressor packs the output into a self-extracting runtime wrapper so the shipped file looks shorter and less readable than the original transformed code.
What it does
This option stores the final script in a packed form and adds a small bootstrap that rebuilds the code when the file runs. The original documentation notes that the wrapper adds roughly 1.3 KB of extraction logic.
Conceptual example
Instead of leaving the transformed code visible, the output becomes a compact wrapper around packed data:
(function () {
var packed = "...";
var source = unpack(packed);
execute(source);
})();
Use it deliberately: Compressor can be useful when you want a harder-to-read single-file result, but it is not always the best choice if your deployment pipeline already applies its own compression and you want the lightest runtime behavior.