Examine source code of Rhythmical black.

{
  "theme": {
    "images": {
      "theme_frame": "b1214-sybmp-4445.jpg"
    },
    "colors": {
      "frame": "#68d4c2",
      "tab_background_text": "#000"
    }
  },
  "version": "2.0",
  "name": "Rhythmical black.",
  "manifest_version": 2,
  "description": "リズミカルな黒。"
}