Examine source code of Letterboxd Services

{
  "manifest_version": 2,
  "name": "Letterboxd Services",
  "description": "Letterboxd extension that provides you helps you watch movies.",
  "version": "0.3",
  "icons": {
    "16": "icons/icon16.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "content_scripts": [
    {
      "run_at": "document_idle",
      "matches": [
        "https://letterboxd.com/film/*"
      ],
      "js": [
        "start.js"
      ]
    }
  ]
}