Examine source code of Refused

{
  "name": "Refused",
  "description": "Block ads on your favorite persian websites.",
  "version": "0.5.0",
  "manifest_version": 2,
  "icons": {
    "48": "images/48.png",
    "96": "images/96.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_popup": "popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "http://*/*",
        "https://*/*"
      ],
      "js": [
        "injects/watcher.js"
      ],
      "run_at": "document_end"
    }
  ],
  "options_ui": {
    "page": "options.html"
  },
  "permissions": [
    "webRequest",
    "webRequestBlocking",
    "tabs",
    "storage",
    "unlimitedStorage",
    "alarms",
    "<all_urls>"
  ],
  "default_locale": "en"
}