Examine source code of Color Test

{
  "name": "Color Test",
  "manifest_version": 2,
  "version": "9.0",
  "theme": {
    "images": {
      "theme_frame": "wp5475508-anime-scenery-4k-wallpapers.jpg"
    },
    "colors": {
      "frame": "rgba(227, 18, 224, 1)",
      "tab_background_text": "rgba(255, 255, 255, 1)",
      "toolbar": "rgba(23, 64, 250, 1)",
      "bookmark_text": "rgba(255, 255, 255, 1)",
      "toolbar_field": "rgba(0, 255, 251, 1)",
      "toolbar_field_text": "rgba(255, 255, 255, 1)",
      "tab_line": "rgba(255, 0, 68, 1)"
    }
  }
}