Examine source code of Ekas Mouseover Previews

{
  "description": "An extension which adds the thumbnail preview already implemented in some places on Ekas, across the whole site.",
  "manifest_version": 2,
  "name": "Ekas Mouseover Previews",
  "version": "1.4",
  "icons": {
    "16": "EMP-16.png",
    "48": "EMP-48.png",
    "128": "EMP-128.png"
  },
  "permissions": [
    "storage"
  ],
  "content_scripts": [
    {
      "matches": [
        "*://aryion.com/g4/*"
      ],
      "js": [
        "jquery-3.4.1.js",
        "contentScript.js"
      ],
      "run_at": "document_end"
    }
  ]
}