Examine source code of PageChopper

{
  "manifest_version": 2,
  "name": "PageChopper",
  "description": "Modify current page for printing.",
  "version": "1.1resigned1",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_icon": {
      "16": "icon-16.png",
      "48": "icon-48.png",
      "128": "icon-128.png"
    },
    "default_title": "Modify page for printing"
  },
  "permissions": [
    "activeTab"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{78596f9b-b0b8-4655-a601-ef5113459f29}"
    }
  }
}