Examine source code of Shopping List Reminder

{
  "manifest_version": 3,
  "name": "__MSG_extensionName__",
  "version": "1.0",
  "description": "__MSG_extensionDescription__",
  "icons": {
    "128": "icons/icon128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{e3d1f3c1-0b9d-2c9e-3f4b-1a3f28dfe1cd}"
    }
  },
  "permissions": [
    "storage",
    "scripting",
    "activeTab"
  ],
  "host_permissions": [
    "*://*.allrecipes.com/*",
    "*://*.foodnetwork.com/*",
    "*://*.epicurious.com/*"
  ],
  "action": {
    "default_popup": "popup/popup.html",
    "default_icon": {
      "128": "icons/icon128.png"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.allrecipes.com/*",
        "*://*.foodnetwork.com/*",
        "*://*.epicurious.com/*"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_idle"
    }
  ]
}