Examine source code of Text Monitors

{
  "manifest_version": 2,
  "name": "Text Monitor",
  "version": "1.0",
  "description": "Monitor specific text on a webpage and get notified when it changes.",
  "permissions": [
    "activeTab",
    "storage",
    "notifications"
  ],
  "browser_action": {
    "default_icon": "icon.png",
    "default_popup": "popup.html",
    "default_title": "Text Monitor"
  },
  "icons": {
    "48": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{1227745e-2ad3-49d1-8d3f-549f7f8c5f2f}"
    }
  }
}