Examine source code of To play with pebbles.

{
  "theme": {
    "images": {
      "theme_frame": "0811-mazu-akarui---.jpg"
    },
    "colors": {
      "frame": "#cccccc",
      "tab_background_text": "#f5f0f0"
    }
  },
  "version": "2.0",
  "name": "To play with pebbles.",
  "manifest_version": 2,
  "description": "小石とあそぶ。。\nTo play with pebbles. \n\n0811-mazu-akarui---"
}