Examine source code of XHR Viewer

{
  "manifest_version": 2,
  "name": "XHR Viewer",
  "version": "1.0",
  "description": "Catch XHR requests and display them in a popup.",
  "permissions": [
    "webRequest",
    "webRequestBlocking",
    "tabs",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true
  },
  "browser_action": {
    "default_icon": {
      "48": "icons/icon48.png",
      "128": "icons/icon128.png"
    },
    "default_title": "XHR Viewer",
    "default_popup": "popup.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{7b85ecfa-1236-4c69-b6dc-327ca694a942}"
    }
  }
}