You're building an application where a specific UI element needs to break out from its parent's stacking context, due to the parent's z-index constraints. What React feature would you leverage to achieve this?

To break out of a parent's stacking context and render a UI element outside its parent, you can use React Portals. Portals allow you to render content at a different location in the DOM hierarchy, which is useful for scenarios like modals or tooltips that need to overlay other elements without being affected by parent z-index constraints.