Examine source code of Koala Search

{
  "manifest_version": 2,
  "name": "Koala Search",
  "version": "1.1",
  "developer": {
    "name": "Arsen Baregamyan",
    "url": "https://baregamyan.com"
  },
  "description": "Improves user experience with keyboard usage on Google Search website.",
  "icons": {
    "48": "icons/koala-48.png",
    "96": "icons/koala-96.png",
    "128": "icons/koala-128.png"
  },
  "applications": {
    "gecko": {
      "id": "baregamyan@gmail.com",
      "strict_min_version": "57.0"
    }
  },
  "browser_action": {
    "default_icon": "icons/koala-32.png",
    "default_title": "Koala Search",
    "default_popup": "popup/popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.google.com/search*"
      ],
      "js": [
        "bundle.js"
      ],
      "css": [
        "style.css"
      ]
    }
  ]
}