proof of concept, its theoritically possible for this extension to work

src/assets/manifest.chrome.json

@@ -1,5 +1,5 @@
 {
   "background": {
-    "service_worker": "index.js"
+    "service_worker": "worker.js"
   }
 }

src/assets/manifest.common.json

@@ -10,7 +10,7 @@
     "default_title": "movie-web extension",
     "default_popup": "popup.html"
   },
-  "permissions": ["storage", "tabs", "cookies", "scripting"],
+  "permissions": ["declarativeNetRequest"],
   "host_permissions": ["<all_urls>"],
   "web_accessible_resources": [
     {

src/assets/manifest.firefox.json

@@ -1,6 +1,6 @@
 {
   "background": {
-    "scripts": ["index.js"]
+    "scripts": ["worker.js"]
   },
   "browser_specific_settings": {
     "gecko": {

src/index.ts

@@ -1,10 +1,36 @@
-chrome.webRequest.onBeforeSendHeaders.addListener(
-  (details) => {
-    console.log(details);
-    return { requestHeaders: details.requestHeaders };
-  },
-  { urls: ['<all_urls>'] },
-  ['blocking', 'requestHeaders'],
-);
+chrome.declarativeNetRequest.updateDynamicRules({
+  removeRuleIds: [666],
+  addRules: [
+    {
+      id: 666,
+      priority: 1,
+      condition: {
+        initiatorDomains: ['movie-web.app'],
+      },
+      action: {
+        type: chrome.declarativeNetRequest.RuleActionType.MODIFY_HEADERS,
+        requestHeaders: [
+          {
+            header: 'X-Test',
+            operation: chrome.declarativeNetRequest.HeaderOperation.SET,
+            value: 'Hello world',
+          },
+        ],
+        responseHeaders: [
+          {
+            header: 'Access-Control-Allow-Origin',
+            operation: chrome.declarativeNetRequest.HeaderOperation.SET,
+            value: '*',
+          },
+          {
+            header: 'Access-Control-Allow-Methods',
+            operation: chrome.declarativeNetRequest.HeaderOperation.SET,
+            value: 'POST,GET,OPTIONS,PUT',
+          },
+        ],
+      },
+    },
+  ],
+});
 
 console.log('loaded extension');

vite.config.ts

@@ -1,4 +1,4 @@
-import { resolve, sep } from 'path'
+import { resolve, dirname } from 'path'
 import { defineConfig } from 'vite'
 import { manifestMerge } from './plugins/manifest';
 import { viteStaticCopy } from 'vite-plugin-static-copy'
@@ -19,12 +19,13 @@ export default defineConfig({
     viteStaticCopy({
       targets: staticAssets.map(file => ({
         src: resolve(__dirname, file),
-        dest: resolve(__dirname, file.replace(/^src/, 'dist')),
+        dest: dirname(resolve(__dirname, file.replace(/^src/, 'dist'))),
       }))
     })
   ],
   root: "src",
   build: {
+    emptyOutDir: true,
     minify: false,
     rollupOptions: {
       output: [{