Examine source code of NEXT!

{
  "manifest_version": 2,
  "name": "NEXT!",
  "version": "1.1resigned1",
  "description": "Go to the next page with just a keystroke",
  "permissions": [
    "tabs"
  ],
  "page_action": {
    "default_icon": "icons/next-gray.svg",
    "default_title": "Next page!"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "icons": {
    "48": "icons/next.svg",
    "96": "icons/next.svg"
  },
  "commands": {
    "_execute_page_action": {
      "suggested_key": {
        "default": "Alt+X"
      }
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{64982ff5-28fc-46bf-b7ee-f92baebc8cc3}"
    }
  }
}