Examine source code of It echoed slowly.

{
  "theme": {
    "images": {
      "theme_frame": "1127-bokasi-maruwaku--oo--wak.jpg"
    },
    "colors": {
      "frame": "#f2f794",
      "tab_background_text": "#2b3eed"
    }
  },
  "version": "2.0",
  "name": "It echoed slowly.",
  "manifest_version": 2,
  "description": "1127-bokasi-maruwaku--oo--wak-"
}