Examine source code of Steampunk

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Steampunk",
  "theme": {
    "images": {},
    "properties": {},
    "colors": {
      "toolbar": "rgb(30, 25, 18)",
      "toolbar_text": "rgb(230, 176, 106)",
      "frame": "rgb(19, 15, 9)",
      "tab_background_text": "rgb(203, 163, 111)",
      "toolbar_field": "rgb(19, 15, 9)",
      "toolbar_field_text": "rgb(203, 163, 111)",
      "tab_line": "rgb(230, 176, 106)",
      "popup": "rgb(30, 25, 18)",
      "popup_text": "rgb(203, 163, 111)",
      "popup_border": "rgb(230, 176, 106)",
      "toolbar_bottom_separator": "rgb(30, 25, 18)",
      "tab_loading": "rgb(230, 176, 106)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{b09c0500-a48e-4ac3-9ab2-7d646e61866e}"
    }
  }
}