Examine source code of LetterWatch

{
  "manifest_version": 2,
  "name": "LetterWatch",
  "version": "1.0.0",
  "description": "See where to watch films directly from your Letterboxd watchlist.",
  "license": "MIT",
  "icons": {
    "48": "icons/icon48.png",
    "96": "icons/icon96.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://letterboxd.com/*"
      ],
      "js": [
        "content.js"
      ],
      "css": [
        "styles.css"
      ],
      "run_at": "document_idle"
    }
  ],
  "permissions": [
    "*://letterboxd.com/*"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{49143982-47ba-442c-8f67-7b7a5fbcdfb0}"
    }
  }
}