Examine source code of Hollow Blue

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Hollow Blue",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-000-5672c42860d5b06e1058dc477397f3ef.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(39, 67, 79)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(52, 85, 101)",
      "tab_background_text": "rgb(242, 242, 242)",
      "toolbar_field": "rgb(32, 55, 64)",
      "toolbar_field_text": "rgb(255, 255, 255)",
      "tab_line": "rgb(54, 132, 168)",
      "popup": "rgb(53, 66, 75)",
      "popup_text": "rgb(255, 255, 255)",
      "button_background_active": "rgb(52, 85, 101)",
      "button_background_hover": "rgb(52, 85, 101)",
      "ntp_background": "rgb(52, 85, 101)",
      "popup_highlight": "rgb(52, 85, 101)",
      "sidebar_highlight_text": "rgb(255, 255, 255)",
      "tab_loading": "rgb(54, 132, 168)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{54ff27e4-69db-4936-be3f-6e82df16532c}"
    }
  }
}