Examine source code of classic dark fade

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "classicdark",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.png",
        "images/1.png"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "right bottom",
        "center top"
      ],
      "additional_backgrounds_tiling": [
        "repeat-y",
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(0, 0, 0, 0)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(0, 0, 0)",
      "tab_background_text": "rgb(117, 117, 117)",
      "toolbar_field": "rgba(0, 0, 0, 0.31)",
      "toolbar_field_text": "rgb(255, 255, 255)",
      "tab_line": "rgb(0, 0, 0)",
      "popup": "rgba(0, 0, 0, 0.53)",
      "popup_text": "rgb(255, 255, 255)",
      "icons": "rgb(221, 221, 221)",
      "ntp_background": "rgb(0, 0, 0)",
      "popup_border": "rgb(0, 0, 0)",
      "tab_selected": "rgb(64, 64, 64)",
      "tab_loading": "rgb(0, 0, 0)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{e2f2c442-5d62-4901-9a2e-029d8e2cc70e}"
    }
  }
}