Examine source code of Highlight for firefox

{
  "manifest_version": 2,
  "name": "Highlight",
  "version": "1.2",
  "description": "Allows the user to highlight and store text from webpages; which can later be viewed in the extensions webpage.",
  "icons": {
    "48": "icons/marker-48.png",
    "64": "icons/marker-64.png"
  },
  "permissions": [
    "activeTab",
    "contextMenus",
    "storage"
  ],
  "browser_action": {
    "default_icon": {
      "32": "icons/marker-32.png"
    },
    "default_title": "Highlight"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  }
}