Examine source code of mechanical colors

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "011023-1",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.jpg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "right top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(137, 139, 139, 0.36)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(130, 132, 132)",
      "tab_background_text": "rgb(255, 255, 255)",
      "toolbar_field": "rgba(15, 15, 15, 0.59)",
      "toolbar_field_text": "rgb(255, 255, 255)",
      "tab_line": "rgb(140, 142, 142)",
      "popup": "rgba(56, 55, 55, 0.98)",
      "popup_text": "rgb(255, 255, 255)",
      "button_background_active": "rgba(32, 33, 33, 0.72)",
      "button_background_hover": "rgba(47, 145, 140, 0.72)",
      "popup_border": "rgba(126, 128, 128, 0)",
      "tab_selected": "rgba(10, 98, 79, 0.34)",
      "toolbar_bottom_separator": "rgba(140, 142, 142, 0.67)",
      "toolbar_field_border_focus": "rgba(0, 0, 0, 0.9)",
      "toolbar_field_border": "rgba(119, 121, 121, 0.93)",
      "toolbar_field_focus": "rgba(90, 116, 116, 0.67)",
      "toolbar_top_separator": "rgba(140, 142, 142, 0.67)",
      "tab_loading": "rgb(140, 142, 142)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{748a6f41-9219-4344-a8a0-eb4b23d60b4f}"
    }
  }
}