Examine source code of New Tab Container

{
  "manifest_version": 2,
  "name": "New Tab Container",
  "version": "1.2resigned1",
  "description": "New Tab Container allows you to specify a container from the Multi Account Containers extension to automatically open all new tabs in.",
  "homepage_url": "https://github.com/remi-gelinas/contain-new-tab",
  "applications": {
    "gecko": {
      "id": "@contain-new-tab",
      "strict_min_version": "57.0"
    }
  },
  "permissions": [
    "contextualIdentities",
    "cookies",
    "management",
    "tabs",
    "storage"
  ],
  "background": {
    "scripts": [
      "js/background.js"
    ]
  },
  "options_ui": {
    "page": "html/options.html",
    "browser_style": true
  }
}