Examine source code of hello_kitty_exts

{
  "manifest_version": 2,
  "version": "2.0",
  "name": "<hello-kitty>",
  "theme": {
    "images": {
      "theme_frame": "288155.jpg"
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "right top",
        "left top"
      ]
    },
    "colors": {
      "frame": "#FFFFFF",
      "tab_background_text": "#000"
    }
  }
}