Examine source code of Stellar Photos

{
  "manifest_version": 2,
  "name": "Stellar Photos",
  "version": "4.1.2",
  "description": "Experience a beautiful photo from Unsplash every time you open a new browser tab",
  "icons": {
    "48": "icons/48.png",
    "64": "icons/64.png",
    "128": "icons/128.png"
  },
  "chrome_url_overrides": {
    "newtab": "index.html"
  },
  "browser_action": {
    "default_popup": "popup.html"
  },
  "permissions": [
    "storage",
    "unlimitedStorage",
    "notifications",
    "alarms"
  ],
  "background": {
    "scripts": [
      "js/background.bundle.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "https://stellar.freshman.tech/*"
      ],
      "js": [
        "js/tab.bundle.js"
      ]
    }
  ],
  "applications": {
    "gecko": {
      "id": "stellar@stellarapp.photos",
      "strict_min_version": "70.0"
    }
  }
}