Examine source code of Image Steam

{
  "name": "__MSG_appName__",
  "version": "0.0.1",
  "manifest_version": 2,
  "description": "__MSG_appDescription__",
  "icons": {
    "16": "icons/icon-16.png",
    "128": "icons/icon-128.png"
  },
  "default_locale": "en",
  "browser_specific_settings": {
    "gecko": {
      "id": "webbery@foxmail.com"
    }
  },
  "background": {
    "scripts": [
      "scripts/background.js"
    ]
  },
  "permissions": [
    "contextMenus",
    "tabs",
    "storage",
    "http://*/*",
    "https://*/*"
  ],
  "options_ui": {
    "page": "options.html"
  },
  "content_scripts": [
    {
      "matches": [
        "http://*/*",
        "https://*/*"
      ],
      "js": [
        "scripts/contentscript.js"
      ],
      "run_at": "document_end",
      "all_frames": false
    }
  ],
  "browser_action": {
    "default_icon": {
      "19": "icons/icon-19.png",
      "38": "icons/icon-38.png"
    },
    "default_title": "Image Steam",
    "default_popup": "popup.html"
  },
  "web_accessible_resources": [
    "styles/bootstrap.min.css",
    "styles/bootstrap-theme.min.css"
  ],
  "applications": {
    "gecko": {
      "id": "my-app-id@mozilla.org"
    }
  }
}