Examine source code of Nebula

{
  "name": "Nebulla",
  "manifest_version": 2,
  "version": "4.0",
  "theme": {
    "images": {
      "theme_frame": "cKXtwd5 - Copy.jpg"
    },
    "colors": {
      "frame": "rgba(229, 230, 232, 1)",
      "tab_background_text": "rgba(255, 255, 255, 1)",
      "bookmark_text": "rgba(255, 255, 255, 1)",
      "toolbar_field": "rgba(59, 59, 59, 1)",
      "toolbar_field_text": "rgba(255, 255, 255, 1)"
    }
  }
}