Examine source code of macOS Catalina Dark

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Catalina Dark",
  "theme": {
    "images": {},
    "properties": {},
    "colors": {
      "toolbar": "rgba(255, 255, 255, 0)",
      "toolbar_text": "rgb(214, 214, 214)",
      "frame": "rgb(60, 60, 60)",
      "tab_background_text": "rgb(177, 177, 177)",
      "toolbar_field": "rgb(101, 101, 101)",
      "toolbar_field_text": "rgb(255, 255, 255)",
      "tab_line": "rgba(140, 89, 87, 0)",
      "popup": "rgb(36, 36, 36)",
      "popup_text": "rgb(185, 185, 185)",
      "button_background_active": "rgb(180, 180, 180)",
      "button_background_hover": "rgb(100, 100, 100)",
      "frame_inactive": "rgb(48, 48, 48)",
      "icons_attention": "rgb(65, 65, 65)",
      "icons": "rgb(214, 214, 214)",
      "ntp_background": "rgb(37, 37, 37)",
      "ntp_text": "rgb(222, 222, 222)",
      "popup_border": "rgb(69, 69, 69)",
      "tab_background_separator": "rgba(255, 255, 255, 0)",
      "tab_loading": "rgb(50, 100, 150)",
      "tab_selected": "rgb(100, 100, 100)",
      "tab_text": "rgb(215, 215, 215)",
      "toolbar_bottom_separator": "rgb(0, 0, 0)",
      "toolbar_field_border_focus": "rgb(50, 100, 150)",
      "toolbar_field_border": "rgba(255, 0, 4, 0)",
      "toolbar_field_focus": "rgba(99, 99, 99, 0)",
      "toolbar_field_highlight_text": "rgb(215, 215, 215)",
      "toolbar_field_highlight": "rgba(100, 100, 100, 0)",
      "toolbar_top_separator": "rgba(255, 0, 4, 0)",
      "toolbar_vertical_separator": "rgba(255, 255, 255, 0)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{630358a7-5e05-4e0b-8012-2ddf81791a89}"
    }
  }
}