Examine source code of Naviseal

{
  "name": "Naviseal",
  "version": "0.3.2",
  "manifest_version": 2,
  "description": "Better navigation while using a keyboard",
  "icons": {
    "16": "/images/naviseal-16.png",
    "32": "/images/naviseal-32.png",
    "48": "/images/naviseal-48.png",
    "64": "/images/naviseal-64.png",
    "128": "/images/naviseal-128.png",
    "256": "/images/naviseal-256.png",
    "512": "/images/naviseal-512.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://www.google.com/search*"
      ],
      "js": [
        "naviseal.js"
      ],
      "run_at": "document_start",
      "all_frames": true
    }
  ]
}