Examine source code of Print as Plain Text

{
  "minimum_chrome_version": "38",
  "name": "Print As Plain Text",
  "short_name": "Print as plain text the content of web pages with rapid preview",
  "icons": {
    "16": "assets/icon_16.png",
    "128": "assets/icon_128.png"
  },
  "manifest_version": 2,
  "applications": {
    "gecko": {
      "id": "@printtextselected",
      "strict_min_version": "48.0"
    }
  },
  "web_accessible_resources": [
    "data/*"
  ],
  "description": "Print as plain text the content of web pages with rapid preview using context menu",
  "homepage_url": "http://mediamaster.eu/contatti",
  "version": "1.8.1resigned1",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "<all_urls>",
    "tabs",
    "webRequest",
    "contextMenus",
    "activeTab"
  ]
}