Examine source code of Note it!

{
  "name": "Note it!",
  "version": "2",
  "description": "To add the notes while browsing sites or just any to-do that comes in mind!",
  "manifest_version": 2,
  "background": {
    "scripts": [
      "js/bg.js"
    ]
  },
  "page_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "images/noteit-16.png",
      "32": "images/noteit-32.png",
      "48": "images/noteit-48.png",
      "128": "images/noteit-128.png"
    }
  },
  "icons": {
    "16": "images/noteit-16.png",
    "32": "images/noteit-32.png",
    "48": "images/noteit-48.png",
    "128": "images/noteit-128.png"
  },
  "permissions": [
    "activeTab",
    "contextMenus",
    "tabs"
  ]
}