Examine source code of Memory Usage Monitor

{
  "manifest_version": 2,
  "name": "Memory Usage Monitor",
  "version": "1.0",
  "description": "Monitor browser memory usage in real-time.",
  "icons": {
    "64": "icon64.png",
    "128": "icon128.png"
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "icon64.png"
  },
  "permissions": [
    "tabs"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{87351afd-d45a-41a0-b4ae-b9f6cc16b929}",
      "strict_min_version": "123.0"
    }
  }
}