Examine source code of HN Enhance

{
  "name": "HN Enhance",
  "manifest_version": 2,
  "author": "Alvaro Bernal",
  "version": "0.1.1resigned1",
  "description": "An extension that enhances news.ycombinator website.",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_icon": "icons/icon-128.png",
    "default_title": "HN Enhance"
  },
  "web_accessible_resources": [
    "*.woff",
    "*.svg"
  ],
  "icons": {
    "16": "icons/icon-16.png",
    "38": "icons/icon-38.png",
    "48": "icons/icon-38.png",
    "128": "icons/icon-128.png"
  },
  "permissions": [],
  "content_scripts": [
    {
      "matches": [
        "http://news.ycombinator.com/*",
        "https://news.ycombinator.com/*"
      ],
      "css": [
        "style.css",
        "ranks.css"
      ],
      "js": [
        "contentscript.js"
      ],
      "run_at": "document_start",
      "all_frames": false
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{74130871-a7e3-4a1f-8ed8-718fd681c4b2}"
    }
  }
}