Examine source code of Open Subtitles

{
  "name": "Open Subtitles",
  "version": "6.3.8",
  "manifest_version": 2,
  "description": "Add subtitles to any HTML5 video sites such as Youtube, Netflix, Amazon Prime Video, Disney+, HBO Max and other stream sites.",
  "author": "Stefan Breitenstein",
  "icons": {
    "16": "res/icons/logo16.png",
    "48": "res/icons/logo48.png",
    "128": "res/icons/logo128.png"
  },
  "browser_action": {
    "default_icon": {
      "16": "res/icons/logo16.png"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "content_security_policy": "script-src 'self'; object-src 'self'",
  "permissions": [
    "activeTab",
    "storage",
    "https://*.plus-sub.com/*",
    "https://gqlos.plus-sub.com/*",
    "https://*.opensubtitles.org/**/*",
    "https://*.opensubtitles.com/**/*",
    "webRequest"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{fa13934b-65d0-4632-b49e-5e4f6cba9168}"
    }
  }
}