Examine source code of Gmail Keyboard Navigation

{
  "name": "Gmail Keyboard Navigation",
  "version": "1.0.0.1",
  "manifest_version": 2,
  "description": "Allows navigating through Gmail labels using the keyboard",
  "browser_action": {
    "default_icon": {
      "16": "icon16.png",
      "24": "icon24.png",
      "32": "icon32.png"
    },
    "default_popup": "popup.html",
    "default_title": "Gmail Keyboard Navigation"
  },
  "icons": {
    "16": "icon16.png",
    "48": "icon48.png",
    "128": "icon128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://mail.google.com/*"
      ],
      "js": [
        "contentscript.js"
      ],
      "run_at": "document_idle",
      "all_frames": false
    }
  ]
}