Examine source code of GommeHD-DarkTheme

{
  "manifest_version": 2,
  "name": "GommeHD-DarkTheme",
  "version": "1.0.2resigned1",
  "permissions": [
    "tabs"
  ],
  "content_scripts": [
    {
      "matches": [
        "*://*.gommehd.net/*"
      ],
      "js": [
        "darktheme.js"
      ],
      "all_frames": true,
      "run_at": "document_end"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{324ae3ff-4d43-438d-a31f-da88be618dd5}"
    }
  }
}