Examine source code of Dark theme

{
  "manifest_version" : 2 ,
  "version" : "1.5",
  "name" : "Dark theme",
  "theme": {
    "images": {},
    "properties": {},
    "colors": {
      "frame": "rgb(25, 25, 25)",
      "toolbar": "rgb(45, 45, 45)",
      "toolbar_text": "rgb(215, 215, 215)",
      "toolbar_field": "rgb(20, 20, 20)",
      "toolbar_field_text": "rgb(255, 255, 255)",
      "tab_selected": "rgba(255, 255, 255, 0.2)",
      "tab_text": "rgb(255, 255, 255)",
      "tab_background_text": "rgb(180, 180, 180)",
      "tab_line": "rgba(255, 255, 255, 0.2)",
      "tab_loading": "rgba(255, 255, 255, 0.2)",
      "icons_attention": "rgb(255, 215, 0)",
      "popup": "rgb(45, 45, 45)",
      "popup_text": "rgb(215, 215, 215)",
      "popup_highlight": "rgba(255, 255, 255, 0.1)",
      "sidebar": "rgb(45, 45, 45)",
      "ntp_background": "rgb(45, 45, 45)",
      "ntp_text": "rgb(255, 255, 255)",
      "ntp_card_background": "rgb(60, 60, 60)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{8879a0ba-42e4-4642-99f2-e1a4a4bce68f}"
    }
  }
}