Examine source code of Sift: IMDB for Netflix, IMDB for Prime, etc. etc.

{
  "manifest_version": 3,
  "name": "Sift: IMDB on Netflix, IMDB on Prime, etc.",
  "description": "Sift adds IMDB ratings next to program tiles on various streaming websites.",
  "version": "9.6.1",
  "icons": {
    "16": "images/logo16.png",
    "32": "images/logo32.png",
    "48": "images/logo48.png",
    "128": "images/logo128.png"
  },
  "author": "anirudh.nimmagadda@gmail.com",
  "content_scripts": [],
  "background": {
    "scripts": [
      "service-worker.js"
    ]
  },
  "action": {
    "default_popup": "popup/index.html",
    "default_icon": "images/logo32.png"
  },
  "permissions": [
    "scripting",
    "storage"
  ],
  "optional_host_permissions": [
    "https://www.amazon.com/*",
    "https://www.amazon.de/*",
    "https://www.primevideo.com/*",
    "https://tv.apple.com/*",
    "https://www.crunchyroll.com/*",
    "https://www.disneyplus.com/*",
    "https://www.hbomax.com/*",
    "https://play.hbomax.com/*",
    "https://www.hotstar.com/*",
    "https://www.hulu.com/*",
    "https://www.mxplayer.in/*",
    "https://www.netflix.com/*",
    "https://www.paramountplus.com/*",
    "https://www.peacocktv.com/*",
    "https://www.sonyliv.com/*",
    "https://www.youtube.com/*",
    "https://www.zee5.com/*"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "sift_imdb_ratings_indian_ott@example.com",
      "strict_min_version": "113.0"
    },
    "gecko_android": {
      "strict_min_version": "113.0"
    }
  }
}