`secret-event-listener` is a tiny Node.js utility that lets you attach listeners to an `EventEmitter` without triggering any of the usual side‑effects (e.g., the `newListener` event, max‑listener warnings, or stream flowing mode). It provides `addSecretListener` (and a `prepend` variant) for developers who need truly silent listeners—typically in testing, instrumentation, or low‑level library code where normal event‑attachment behavior would interfere.