Examine source code of Tide is flowing.

{
  "theme": {
    "images": {
      "theme_frame": "708-greenboyaan--bu4---lu-dandan.jpg"
    },
    "colors": {
      "frame": "#f3dcf5",
      "tab_background_text": "#000000"
    }
  },
  "version": "2.0",
  "name": "Tide is flowing.",
  "manifest_version": 2,
  "description": "流れる潮。～"
}