Examine source code of Letterboxd FA

{
  "manifest_version": 2,
  "name": "Letterboxd FA",
  "version": "1.0",
  "description": "Adds Farsi Support to Letterboxd",
  "icons": {
    "48": "icons/letterboxd-48.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://letterboxd.com/*"
      ],
      "js": [
        "jquery-3.4.1.min.js",
        "main.js"
      ],
      "css": [
        "main.css"
      ]
    }
  ]
}