Examine source code of Cielo nocturno

{
  "name": "Cielo estrellado",
  "manifest_version": 2,
  "version": "2.0",
  "theme": {
    "images": {
      "theme_frame": "Screenshot-2018-5-1 1 Hour Beautiful Piano Music for Studying and Sleeping【作業用BGM】 - YouTube(5).png"
    },
    "colors": {
      "toolbar": "rgba(250, 250, 250, 0.15)",
      "toolbar_field": "rgba(250, 237, 249, 0.11)",
      "toolbar_field_text": "rgba(23, 21, 23, 0.95)",
      "frame": "rgba(227, 229, 232, 0.39)",
      "tab_background_text": "rgba(250, 245, 245, 1)",
      "bookmark_text": "rgba(255, 255, 255, 0.94)"
    }
  }
}