Examine source code of Koe-Koe

{
  "manifest_version": 2,
  "name": "Koe-Koe",
  "version": "1.2",
  "description": "Add download button to koe-koe.com posts.",
  "content_scripts": [
    {
      "matches": [
        "*://koe-koe.com/detail.php*"
      ],
      "js": [
        "koekoe.js"
      ]
    }
  ]
}