Examine source code of Adwaita Dark

{
  "manifest_version": 2,
  "version": "1.1",
  "name": "Adwaita Dark",
  "theme": {
    "images": {},
    "properties": {},
    "colors": {
      "toolbar": "rgb(63, 63, 63)",
      "toolbar_text": "rgb(245, 245, 245)",
      "frame": "rgb(48, 48, 48)",
      "tab_background_text": "rgb(192, 192, 192)",
      "toolbar_field": "rgb(30, 30, 30)",
      "toolbar_field_text": "rgb(245, 245, 245)",
      "tab_line": "rgb(79, 79, 79)",
      "popup": "rgb(30, 30, 30)",
      "popup_text": "rgb(245, 245, 245)",
      "frame_inactive": "rgb(36, 36, 36)",
      "icons_attention": "rgb(53, 132, 228)",
      "ntp_background": "rgb(47, 46, 46)",
      "popup_border": "rgb(48, 48, 48)",
      "tab_selected": "rgb(79, 79, 79)",
      "toolbar_field_border_focus": "rgb(42, 81, 129)",
      "tab_loading": "rgb(79, 79, 79)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{79def90a-63f8-4ea0-bf55-fcebc7081f3d}"
    }
  }
}