Examine source code of maycat

{
  "theme": {
    "images": {
      "theme_frame": "DSC_0205_edited-1.jpg"
    },
    "colors": {
      "frame": "#cf1313",
      "tab_background_text": "#0a8a12"
    }
  },
  "version": "2.0",
  "name": "maycat",
  "manifest_version": 2,
  "description": "夕日の中の湖にいる白鳥。"
}