Examine source code of Header Editor

{
  "name": "Header Editor",
  "short_name": "Header Editor",
  "version": "5.2.12",
  "description": "__MSG_description__",
  "homepage_url": "https://he.firefoxcn.net",
  "icons": {
    "128": "assets/images/128.png"
  },
  "permissions": [
    "tabs",
    "storage",
    "unlimitedStorage",
    "webRequest",
    "webRequestBlocking",
    "declarativeNetRequest",
    "*://*/*"
  ],
  "default_locale": "en",
  "options_ui": {
    "page": "options.html",
    "open_in_tab": true
  },
  "manifest_version": 2,
  "browser_action": {
    "default_icon": {
      "128": "assets/images/128.png"
    },
    "default_title": "__MSG_extButtonTitle__",
    "default_popup": "popup.html"
  },
  "background": {
    "scripts": [
      "assets/js/background.js"
    ]
  },
  "content_security_policy": "script-src 'self' 'unsafe-eval'; object-src 'self';",
  "browser_specific_settings": {
    "gecko": {
      "id": "headereditor-amo@addon.firefoxcn.net",
      "strict_min_version": "113.0"
    }
  }
}