Examine source code of Subtle Amber

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Subtle Amber",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-010-e9f94a3e61666a4c7677eb9cce17d854.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(0, 0, 0)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(0, 0, 0)",
      "tab_background_text": "rgb(255, 255, 255)",
      "toolbar_field": "rgb(0, 0, 0)",
      "toolbar_field_text": "rgb(255, 255, 255)",
      "tab_line": "rgb(255, 131, 0)",
      "popup": "rgb(0, 0, 0)",
      "popup_text": "rgb(255, 255, 255)",
      "button_background_active": "rgb(255, 131, 0)",
      "button_background_hover": "rgb(255, 255, 255)",
      "frame_inactive": "rgb(255, 131, 0)",
      "icons": "rgb(59, 59, 59)",
      "popup_border": "rgb(255, 103, 0)",
      "popup_highlight": "rgb(255, 110, 0)",
      "sidebar_border": "rgb(255, 131, 0)",
      "sidebar_highlight_text": "rgb(255, 131, 0)",
      "sidebar_highlight": "rgb(255, 131, 0)",
      "sidebar": "rgb(0, 0, 0)",
      "tab_selected": "rgb(0, 0, 0)",
      "toolbar_field_border_focus": "rgb(255, 131, 0)",
      "tab_loading": "rgb(255, 131, 0)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{ad67c083-1d3d-4d57-9f0d-5a998403718b}"
    }
  }
}