Examine source code of Topographic Black

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Topographic Black",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.png"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "center top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(4, 4, 4)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(8, 11, 33)",
      "tab_background_text": "rgb(215, 226, 239)",
      "toolbar_field": "rgb(42, 45, 60)",
      "toolbar_field_text": "rgb(255, 255, 255)",
      "tab_line": "rgb(63, 63, 63)",
      "popup": "rgb(4, 4, 4)",
      "popup_text": "rgb(215, 226, 239)",
      "frame_inactive": "rgb(27, 20, 60)",
      "tab_loading": "rgb(63, 63, 63)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{d9e39ee2-885b-4ed6-93e5-608fdcaf10fb}"
    }
  }
}