Examine source code of viality_skyline_hell

{
  "theme": {
    "images": {
      "theme_frame": "skyline_hell.jpg"
    },
    "colors": {
      "frame": "#dedede",
      "tab_background_text": "#363636"
    }
  },
  "version": "2.0",
  "name": "viality_skyline_hell",
  "manifest_version": 2
}