Examine source code of Paraphrasing.io

{
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_action": {
    "default_icon": "icons/19.png"
  },
  "content_scripts": [
    {
      "js": [
        "content.js"
      ],
      "matches": [
        "<all_urls>"
      ]
    }
  ],
  "description": "paraphrasing.io is an online tool that Paraphrase the selected text.",
  "homepage_url": "https://paraphrasing.io/",
  "icons": {
    "16": "icons/16.png",
    "48": "icons/48.png",
    "128": "icons/128.png"
  },
  "manifest_version": 2,
  "name": "paraphrasing.io",
  "permissions": [
    "activeTab",
    "https://ajax.googleapis.com/",
    "http://www.prepostseo.com/",
    "https://www.prepostseo.com/",
    "contextMenus"
  ],
  "version": "0.0.1"
}