Examine source code of YTLooper

{
  "manifest_version": 2,
  "name": "YTLooper",
  "version": "1.2.4resigned1",
  "description": "Allows you to loop YouTube videos with one click.",
  "icons": {
    "48": "icons/48Black.png",
    "96": "icons/96Black.png"
  },
  "content_scripts": [
    {
      "run_at": "document_start",
      "matches": [
        "*://*.youtube.com/*"
      ],
      "css": [
        "looper.css"
      ],
      "js": [
        "jquery-3.2.1.slim.min.js",
        "looper.js"
      ]
    }
  ],
  "permissions": [],
  "browser_specific_settings": {
    "gecko": {
      "id": "{36dfbd0b-953c-4359-9239-951383c18649}"
    }
  }
}