Examine source code of AnimeKai Sync

{
  "manifest_version": 2,
  "name": "AnimeKai Sync",
  "version": "1.0",
  "description": "Watch anime in sync with your bro, no matter where he is!",
  "browser_specific_settings": {
    "gecko": {
      "id": "animekai-sync@onepiece",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "permissions": [
    "storage",
    "tabs",
    "*://animekai.to/*",
    "*://www.animekai.to/*"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "48": "icons/icon48.png",
      "128": "icons/icon128.png"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "*://animekai.to/*",
        "*://www.animekai.to/*"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_idle"
    }
  ]
}