Examine source code of Automail

{
  "manifest_version": 2,
  "name": "Automail",
  "version": "9.99.40",
  "description": "Extra parts for Anilist.co",
  "icons": {
    "48": "icons/automail-48.png",
    "96": "icons/automail-96.png",
    "128": "icons/automail-128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://anilist.co/*"
      ],
      "js": [
        "automail.js"
      ]
    }
  ],
  "permissions": [
    "*://graphql.anilist.co/*",
    "*://myanimelist.net/*",
    "webRequest"
  ]
}