Tests <object>, <embed>, and related embedded-resource fetch paths. These elements use a distinct fetch type (object/embed) that some WebView filter implementations handle separately from XHR/fetch or img. <object> can load arbitrary MIME types (HTML, PDF, SWF, arbitrary data) and has its own browsing context. <embed> triggers plugin-load attempts.

An onload/onerror detection pattern is used where available; a CORS oracle confirms domain reachability for channels that do not fire JS events reliably.