Examine source code of Grün Dark

{
  "manifest_version": 2,
  "version": "3.0",
  "name": "Grün Dark",
  "theme": {
    "images": {},
    "properties": {},
    "colors": {
      "toolbar": "rgb(55, 78, 74)",
      "toolbar_text": "rgb(199, 220, 208)",
      "frame": "rgb(49, 54, 56)",
      "tab_background_text": "rgb(199, 220, 208)",
      "toolbar_field": "rgb(55, 78, 74)",
      "toolbar_field_text": "rgb(199, 220, 208)",
      "tab_line": "rgb(84, 126, 100)",
      "popup": "rgb(55, 78, 74)",
      "popup_text": "rgb(199, 220, 208)",
      "ntp_background": "rgb(55, 78, 74)",
      "ntp_text": "rgb(255, 255, 255)",
      "popup_border": "rgb(55, 78, 74)",
      "popup_highlight_text": "rgb(46, 34, 47)",
      "sidebar_border": "rgb(55, 78, 74)",
      "sidebar_highlight_text": "rgb(46, 34, 47)",
      "sidebar_highlight": "rgb(255, 255, 255)",
      "sidebar_text": "rgb(255, 255, 255)",
      "sidebar": "rgb(55, 78, 74)",
      "tab_loading": "rgb(178, 186, 144)",
      "tab_selected": "rgb(84, 126, 100)",
      "tab_text": "rgb(255, 255, 255)",
      "toolbar_bottom_separator": "rgb(55, 78, 74)",
      "toolbar_field_focus": "rgba(55, 78, 74, 0.84)",
      "toolbar_field_highlight_text": "rgb(55, 78, 74)",
      "toolbar_field_highlight": "rgb(255, 255, 255)",
      "toolbar_field_text_focus": "rgb(255, 255, 255)",
      "toolbar_top_separator": "rgb(49, 54, 56)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{0289cc2c-a4eb-4f2b-9d85-7d7d72a855e6}"
    }
  }
}