Examine source code of hjkl

{
  "manifest_version": 2,
  "name": "hjkl",
  "version": "1.2",
  "description": "Adds vim-style navigation keys to your web browser.",
  "icons": {
    "48": "icons/no_mouse.png"
  },
  "browser_action": {
    "default_icon": "icons/no_mouse.png",
    "default_popup": "popup.html",
    "default_title": "HJKL Settings"
  },
  "permissions": [
    "storage"
  ],
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "js": [
        "hjkl.js",
        "popup.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{9be68c25-cfe1-45ad-ac0e-244046f4406d}"
    }
  }
}