GMPolyfill: add header prop (#543)

browser/GMPolyfill.js

@@ -92,6 +92,7 @@ function GM_fetch(url, opt) {
                         resp.arrayBuffer = () => blobTo("arrayBuffer", blob);
                         resp.text = () => blobTo("text", blob);
                         resp.json = async () => JSON.parse(await blobTo("text", blob));
+                        resp.headers = new Headers(parseHeaders(resp.responseHeaders));
                         resolve(resp);
                     };
                     options.ontimeout = () => reject("fetch timeout");

src/utils/constants.ts

@@ -201,5 +201,9 @@ export const Devs = /* #__PURE__*/ Object.freeze({
     lewisakura: {
         name: "lewisakura",
         id: 96269247411400704n
+    },
+    cloudburst: {
+        name: "cloudburst",
+        id: 892128204150685769n
     }
 });