Examine source code of Metro for Firefox

{
  "manifest_version": 2,
  "version": "1.1",
  "name": "Metro for Firefox",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-021-775b159da029a74f5c76e835cd65e9dc.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(17, 17, 17, 0.9)",
      "toolbar_text": "rgb(143, 143, 143)",
      "frame": "rgb(17, 17, 17)",
      "tab_background_text": "rgb(143, 143, 143)",
      "toolbar_field": "rgba(50, 50, 50, 0.22)",
      "toolbar_field_text": "rgb(64, 164, 255)",
      "tab_line": "rgb(64, 164, 255)",
      "popup": "rgb(17, 17, 17)",
      "popup_text": "rgb(203, 203, 203)",
      "tab_loading": "rgb(64, 164, 255)",
      "ntp_background": "rgb(17, 17, 17)",
      "ntp_text": "rgb(143, 143, 143)"
    }
  }
}