Examine source code of Newgrounds MVSX

{
  "manifest_version": 2,
  "name": "Newgrounds MVSX",
  "description": "Newgrounds Matrix adVancement Server Extension",
  "version": "0.4",
  "icons": {
    "48": "icons/icon-tank.svg",
    "96": "icons/icon-tank.svg"
  },
  "permissions": [
    "activeTab",
    "cookies",
    "menus",
    "storage"
  ],
  "page_action": {
    "browser_style": true,
    "default_icon": "icons/icon-head.svg",
    "default_title": "View submission in Matrix",
    "show_matches": [
      "https://www.newgrounds.com/portal/view/*"
    ]
  },
  "background": {
    "scripts": [
      "background-script.js"
    ]
  }
}