Examine source code of Rainbow Theme

{
  "name": "Dark n Red",
  "manifest_version": 2,
  "version": "2.0",
  "theme": {
    "images": {
      "theme_frame": "Unbenannt.png"
    },
    "colors": {
      "frame": "rgba(0, 0, 0, 0)",
      "tab_background_text": "rgba(0, 0, 0, 0.15)",
      "toolbar": "rgba(0, 0, 0, 0.35)",
      "bookmark_text": "rgba(0, 0, 0, 0.25)",
      "toolbar_field": "rgba(3, 3, 3, 0.26)",
      "toolbar_field_text": "rgba(255, 255, 255, 0.5)"
    }
  }
}