Examine source code of Steam HLTB

{
  "manifest_version": 3,
  "name": "Steam HLTB",
  "browser_specific_settings": {
    "gecko": {
      "id": "{b5e7c4a1-8f3d-4e2a-9c6b-1d4e7f8a2b3c}",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "version": "1.0.0",
  "description": "Displays HowLongToBeat times on Steam game pages",
  "permissions": [
    "tabs",
    "scripting"
  ],
  "host_permissions": [
    "https://howlongtobeat.com/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://store.steampowered.com/app/*"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "background": {
    "service_worker": "background.js",
    "scripts": [
      "background.js"
    ]
  },
  "icons": {
    "16": "icons/icon-16.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  }
}