Examine source code of Dark Rainbow Spectrum

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Rainbow Spectrum",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.png"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "left top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(34, 34, 34, 0.75)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(0, 0, 0)",
      "tab_background_text": "rgb(255, 255, 255)",
      "toolbar_field": "rgb(0, 0, 0)",
      "toolbar_field_text": "rgb(255, 255, 255)",
      "tab_line": "rgb(102, 102, 102)",
      "popup": "rgb(34, 34, 34)",
      "popup_text": "rgb(255, 255, 255)",
      "toolbar_bottom_separator": "rgb(0, 0, 0)",
      "toolbar_top_separator": "rgb(0, 0, 0)",
      "tab_loading": "rgb(102, 102, 102)"
    }
  }
}