Examine source code of h-extract

{
  "name": "h-extract",
  "version": "1.0",
  "description": "Download buncha gelbooru image at once!",
  "manifest_version": 2,
  "background": {
    "scripts": [
      "background_script.js"
    ]
  },
  "permissions": [
    "tabs",
    "downloads",
    "*://gelbooru.com/*"
  ],
  "browser_action": {
    "default_icon": {
      "48": "Fingerprinters.svg"
    },
    "default_title": "h-extract"
  }
}