Examine source code of 4 AM

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "4 AM",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-008-60d2718f8c915b5ba09f31df5555b459.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(13, 14, 18)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(13, 14, 18)",
      "tab_background_text": "rgb(255, 255, 255)",
      "toolbar_field": "rgba(75, 77, 78, 0.53)",
      "toolbar_field_text": "rgb(255, 255, 255)",
      "tab_line": "rgb(59, 63, 64)",
      "popup": "rgb(42, 44, 52)",
      "popup_text": "rgb(255, 255, 255)",
      "button_background_hover": "rgb(80, 81, 88)",
      "ntp_background": "rgb(24, 24, 32)",
      "tab_selected": "rgba(75, 77, 78, 0.8)",
      "tab_loading": "rgb(59, 63, 64)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{ef9a1767-28f5-4808-b043-aa3960d15e8f}"
    }
  }
}