Examine source code of Bitok Helper

{
  "manifest_version": 2,
  "name": "Bitok Helper",
  "version": "1.2.1",
  "author": "Ali Rashidi, Amirhossein Azimyzadeh",
  "description": "Directly join virtual classes from el.yazd.ac.ir/vclass",
  "icons": {
    "48": "icons/bitok-48.png",
    "96": "icons/bitok-96.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.el.yazd.ac.ir/vclass*"
      ],
      "js": [
        "bitok-helper.js",
        "./recently_used/index.js"
      ],
      "css": [
        "styles.css"
      ]
    }
  ]
}