Ask HN: Anybody know of a web viewport application?

Does anybody know of an application that displays web code, rendered HTML/CSS and executes JavaScript, but does almost nothing else? Ultimately, I would like to have an application that has no security and can only make network calls to localhost or talk to localhost via some API but does nothing else a modern web browser does besides execution frontend code. As a bonus it would be nice if would support extended features via a build option like WebGPU and WASM.