Examine source code of Opera GX Dark

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Opera GX Dark",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-000-5672c42860d5b06e1058dc477397f3ef.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(43, 43, 43)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(0, 0, 0)",
      "tab_background_text": "rgb(255, 255, 255)",
      "toolbar_field": "rgb(0, 0, 0)",
      "toolbar_field_text": "rgb(255, 255, 255)",
      "tab_line": "rgb(255, 2, 2)",
      "popup": "rgb(38, 38, 38)",
      "popup_text": "rgb(255, 255, 255)",
      "button_background_active": "rgb(30, 30, 30)",
      "button_background_hover": "rgb(25, 25, 25)",
      "icons_attention": "rgb(255, 255, 255)",
      "icons": "rgb(255, 255, 255)",
      "ntp_background": "rgb(40, 40, 40)",
      "popup_border": "rgb(35, 35, 35)",
      "popup_highlight": "rgb(255, 255, 255)",
      "sidebar_border": "rgb(0, 0, 0)",
      "sidebar": "rgb(69, 68, 78)",
      "tab_background_separator": "rgb(255, 255, 255)",
      "tab_selected": "rgb(0, 0, 0)",
      "toolbar_bottom_separator": "rgb(50, 50, 50)",
      "toolbar_field_border": "rgb(3, 3, 3)",
      "toolbar_top_separator": "rgb(255, 0, 31)",
      "toolbar_vertical_separator": "rgb(255, 255, 255)",
      "tab_loading": "rgb(255, 2, 2)"
    }
  }
}