Examine source code of Dark Victorian Pattern

{
  "theme": {
    "images": {
      "theme_frame": "VictorianPattern.png"
    },
    "colors": {
      "frame": "#f2f2f2",
      "tab_background_text": "#e6e6e6"
    }
  },
  "version": "2.0",
  "name": "Dark Victorian Pattern",
  "manifest_version": 2,
  "description": "A simple dark pattern that reminds me the Victorian Ages."
}