Examine source code of easyVim

{
  "manifest_version": 2,
  "name": "easyVim",
  "version": "1.0.4",
  "description": "Vim inspired key bindings for browser.",
  "icons": {
    "96": "icons/icon-enabled.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "contentScript.js"
      ]
    }
  ],
  "permissions": [
    "<all_urls>",
    "tabs"
  ],
  "browser_action": {
    "default_icon": "icons/icon-enabled.png",
    "default_title": "easyVim"
  },
  "background": {
    "scripts": [
      "script.js"
    ]
  }
}