Examine source code of Next-Page

{
  "manifest_version": 2,
  "name": "NextPage",
  "version": "1.1resigned1",
  "description": "Navigate to next/previous if page URL contains a Id as parameter.",
  "icons": {
    "48": "icons/right-48.png"
  },
  "permissions": [
    "activeTab",
    "tabs"
  ],
  "page_action": {
    "browser_style": true,
    "default_icon": {
      "32": "icons/right-32.png"
    },
    "default_title": "next page"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{73a68de0-c603-4323-884d-d1c3b93ceba0}"
    }
  }
}