Bron is a minimalist, zero‑dependency test runner for Node.js that provides a single `test()` function (with `.skip()` and `.only()` modifiers), supports synchronous, async, and promise‑based tests, runs them in parallel by default, and offers simple CLI options for serial execution and timeouts. It’s aimed at developers of small to medium Node projects who want a fast, tiny testing tool without the overhead of larger frameworks. (Note: the author marks it as deprecated now that Node includes a built‑in test runner.)