Examine source code of TimeBlockers

{
  "manifest_version": 2,
  "name": "TimeBlocker",
  "version": "1.0",
  "description": "Block websites on schedule and boost your productivity.",
  "permissions": [
    "storage",
    "notifications"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "48": "icon.png"
    }
  },
  "icons": {
    "48": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{143b57ac-cba8-4582-b592-fa7761e8576e}"
    }
  }
}