Of course, there are underlying utilities that enhance the components. The resulting components are standard web components.
From Stencil's website [1]:
> Stencil is a compiler that generates Web Components (more specifically, Custom Elements) and builds high performance web apps. Stencil combines the best concepts of the most popular frameworks into a simple build-time tool.
> Stencil takes features such as Virtual DOM, async rendering (inspired by React Fiber), reactive data-binding, TypeScript, JSX, and Static Site Generation (SSG) and then generates standards-based Web Components and web apps with these features baked in.
