preact-transition-group provides React-like transition group functionality for Preact. It simplifies managing component entrance and exit animations. The package includes components for defining transitions, handling lifecycle hooks (like componentWillAppear, componentWillEnter, componentWillLeave, componentDidAppear, componentDidEnter, and componentDidLeave), and applying CSS classes during different transition states allowing for declarative and well-defined animations with Preact components using CSS transitions or animations.