Examine source code of QuantumEdge Dark

{
  "description": "QuantumEdge Dark is a theme made using the new Theme API introduced in Firefox 60+.",
  "manifest_version": 2,
  "name": "QuantumEdge Dark",
  "permissions": [
    "theme"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "version": "1.3.3",
  "applications": {
    "gecko": {
      "strict_min_version": "60.0a1"
    }
  }
}