Examine source code of Ficbook+

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "manifest_version": 2,
  "name": "Ficbook+",
  "description": "Improved Ficbook interactions and overall look.",
  "version": "1.7.3",
  "author": "Lemis",
  "browser_action": {
    "default_icon": "/icons/icon128.png",
    "default_popup": "/popup/popup.html"
  },
  "icons": {
    "16": "/icons/icon16.png",
    "48": "/icons/icon48.png",
    "64": "/icons/icon64.png",
    "128": "/icons/icon128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://ficbook.net/*"
      ],
      "js": [
        "/js/fit.js",
        "/js/counters.js",
        "/js/siteFont.js",
        "/js/textFont.js",
        "/js/restyle.js",
        "/js/system.js"
      ]
    }
  ],
  "permissions": [
    "storage"
  ]
}