Examine source code of city white line

{
  "name": "city",
  "manifest_version": 2,
  "version": "2.0",
  "theme": {
    "images": {
      "theme_frame": "k.JPG"
    },
    "colors": {
      "toolbar": "rgba(31, 24, 24, 0.81)",
      "toolbar_field": "rgba(176, 14, 14, 0.6)",
      "toolbar_field_text": "rgba(15, 0, 0, 0.81)",
      "frame": "rgba(171, 176, 186, 0.5)",
      "tab_background_text": "rgba(247, 220, 220, 0.72)",
      "bookmark_text": "rgba(199, 40, 40, 0.61)"
    }
  }
}