The **@ember/test-waiters** addon adds a lightweight, production‑safe API that lets Ember apps and addons mark custom asynchronous work (e.g., CSS transitions, IndexedDB, fetches, ember‑concurrency tasks) so Ember’s test helpers can wait for it to settle. It is intended for Ember developers who need deterministic, debuggable test isolation for async operations beyond what the built‑in “settled” checks cover.