Examine source code of Emacs Dvorak Keybinding

{
  "manifest_version": 2,
  "name": "Emacs-Dvorak-keybinding",
  "description": "An addon for using Firefox with Emacs Dvorak keybinding",
  "version": "0.1.4resigned1",
  "homepage_url": "https://github.com/huytd/emacs-keybinding",
  "author": "Wang Kai ft. Huy Tran",
  "permissions": [
    "tabs",
    "activeTab"
  ],
  "icons": {
    "48": "icons/emacs-48.png",
    "96": "icons/emacs-96.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "keybindings.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{b89896f0-5376-4a1c-b865-899be049c078}"
    }
  }
}