Examine source code of Saving Button

{
  "name": "__MSG_name__",
  "version": "1.0.28",
  "description": "__MSG_description__",
  "author": "Inspiring Benefits",
  "manifest_version": 2,
  "default_locale": "en",
  "permissions": [
    "tabs",
    "webRequest",
    "storage",
    "<all_urls>",
    "unlimitedStorage",
    "cookies"
  ],
  "background": {
    "scripts": [
      "vendors/bundle.js",
      "bg/bundle.js"
    ],
    "persistent": true
  },
  "content_scripts": [
    {
      "all_frames": false,
      "js": [
        "vendors/bundle.js",
        "content/bundle.js"
      ],
      "matches": [
        "<all_urls>"
      ],
      "run_at": "document_end"
    }
  ],
  "options_ui": {
    "page": "settings.html",
    "open_in_tab": true
  },
  "browser_action": {
    "default_icon": "icon-32.png",
    "default_title": "Savings add-on",
    "default_popup": "popup.html"
  },
  "icons": {
    "16": "icon-16.png",
    "32": "icon-32.png",
    "128": "icon-128.png"
  },
  "web_accessible_resources": [
    "content/*.css",
    "content/*.svg",
    "icon-32.png"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{2e680307-0747-4777-b6eb-0d18f457b73e}"
    }
  }
}