Examine source code of mangadex follows image

{
  "manifest_version": 2,
  "name": "mangadexFollowImage",
  "version": "1.0",
  "description": "Adds image for manga updates in the follows page, with lazyload",
  "icons": {
    "48": "icons/border-48.png"
  },
  "applications": {
    "gecko": {
      "id": "mangadexFollowImage@rokuem"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "https://mangadex.org/follows"
      ],
      "js": [
        "main.js"
      ]
    }
  ]
}