Examine source code of SoundCloud Night Mode

{
  "manifest_version": 2,
  "name": "soundcloud_night_mode",
  "description": "Theme soundcloud.com with a darker (night mode) theme",
  "version": "1.2.1resigned1",
  "icons": {
    "48": "icons/icon.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.soundcloud.com/*"
      ],
      "css": [
        "data/soundcloud.min.css"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "@soundcloud_night_mode"
    }
  }
}