Examine source code of Nights Like This

{
  "manifest_version": 2,
  "version": "1.1",
  "name": "Nights Like This",
  "theme": {
    "images": {},
    "properties": {},
    "colors": {
      "toolbar": "rgb(209, 201, 192)",
      "toolbar_text": "rgb(0, 0, 0)",
      "frame": "rgb(48, 52, 61)",
      "tab_background_text": "rgb(255, 255, 255)",
      "toolbar_field": "rgb(209, 201, 192)",
      "toolbar_field_text": "rgb(0, 0, 0)",
      "tab_line": "rgb(255, 159, 0)",
      "popup": "rgb(233, 229, 224)",
      "popup_text": "rgb(0, 0, 0)",
      "popup_highlight": "rgb(37, 116, 184)",
      "sidebar_border": "rgb(43, 42, 51)",
      "sidebar_highlight_text": "rgb(255, 255, 255)",
      "sidebar_highlight": "rgb(37, 116, 184)",
      "sidebar": "rgb(233, 229, 224)",
      "toolbar_bottom_separator": "rgb(174, 167, 160)",
      "toolbar_field_border_focus": "rgb(174, 167, 160)",
      "toolbar_field_focus": "rgba(233, 229, 224, 0.98)",
      "toolbar_field_highlight": "rgb(37, 116, 184)",
      "tab_loading": "rgb(255, 159, 0)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{1b486c98-6290-47ae-afad-07f475b8e7f7}"
    }
  }
}