Examine source code of Futuristic Material

{
  "manifest_version": 2,
  "version": "1.14",
  "name": "Futuristic Material",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-001-9c6d74e14860e77ee6f8f43e824bff25.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "tab_line": "rgb(252, 192, 192)",
      "tab_background_text": "rgb(252, 192, 192)",
      "frame": "rgb(65, 88, 138)",
      "tab_loading": "rgb(252, 192, 192)", // Firefox 60
      "icons_attention": "rgb(185, 234, 250)", // Firefox 60

      "toolbar": "rgb(52, 66, 97)",
      "bookmark_text": "rgb(185, 234, 250)",
      "toolbar_top_separator": "rgba(45, 57, 84, 0.97)",
	  "toolbar_bottom_separator": "rgba(45, 57, 84, 0.97)",
      "toolbar_vertical_separator": "rgba(185, 234, 250, 0.2)",

      "toolbar_field": "rgb(89, 115, 152)",
      "toolbar_field_text": "rgb(185, 234, 250)",
	  "toolbar_field_highlight": "rgb(252, 192, 192)",
	  "toolbar_field_highlight_text": "black",
	  "toolbar_field_border_focus": "rgba(185, 234, 250, 0.8)",
      "toolbar_field_separator": "rgba(185, 234, 250, 0.2)", // Firefox 59

      "button_background_hover": "rgb(89, 115, 152)", // Firefox 60
      "button_background_active": "#466796", // Firefox 60

      "popup": "rgb(52, 66, 97)", // Firefox 60
      "popup_text": "rgb(185, 234, 250)", // Firefox 60
	  "popup_highlight": "rgb(185, 234, 250)",
	  "popup_highlight_text": "black",
      "popup_border": "rgba(45, 57, 84, 0.97)",

      "ntp_text": "white", // Firefox 63
      "ntp_background": "rgb(52, 66, 97)", // Firefox 63

      "sidebar": "rgb(46, 59, 86)", // Firefox 63
      "sidebar_text": "rgb(185, 234, 250)", // Firefox 63
      "sidebar_border": "rgba(45, 57, 84, 0.97)", // Firefox 64
      "sidebar_highlight": "rgb(89, 115, 152)" // Firefox 63
    }
  }
}