Examine source code of Navy gone dark

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Navy gone dark",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-029-cc9cab928c1799136d18758709e91ecc.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(54, 83, 100)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(19, 65, 105)",
      "tab_background_text": "rgb(255, 255, 255)",
      "toolbar_field": "rgb(201, 214, 232)",
      "toolbar_field_text": "rgb(0, 0, 0)",
      "tab_line": "rgb(0, 47, 167)",
      "popup": "rgb(31, 34, 61)",
      "popup_text": "rgb(255, 255, 255)",
      "button_background_hover": "rgb(70, 120, 170)",
      "frame_inactive": "rgb(85, 97, 105)",
      "ntp_background": "rgb(137, 168, 143)",
      "tab_loading": "rgb(0, 47, 167)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{33c02baa-2b20-47d3-bb32-bf52615d716d}"
    }
  }
}