Examine source code of Twitch Dev Dark Theme

{
  "manifest_version": 2,
  "name": "Twitch Dev Dark Theme",
  "version": "1.0",
  "description": "Changes the background color of dev.twitch.dev to rgb(36, 36, 36) and color white.",
  "permissions": [
    "activeTab"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://dev.twitch.tv/*"
      ],
      "css": [
        "styles.css"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{d078af9e-9257-4c05-a99a-2d16e0f0fe4e}"
    }
  }
}