Examine source code of Flat Black

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Flat Black",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-008-60d2718f8c915b5ba09f31df5555b459.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(26, 26, 26)",
      "toolbar_text": "rgb(153, 153, 153)",
      "frame": "rgb(22, 22, 22)",
      "tab_background_text": "rgb(153, 153, 153)",
      "toolbar_field": "rgb(26, 26, 26)",
      "toolbar_field_text": "rgb(179, 179, 179)",
      "tab_line": "rgb(26, 26, 26)",
      "popup": "rgb(26, 26, 26)",
      "popup_text": "rgb(140, 140, 140)",
      "button_background_active": "rgb(17, 17, 17)",
      "button_background_hover": "rgb(26, 26, 26)",
      "frame_inactive": "rgb(30, 30, 30)",
      "icons_attention": "rgb(0, 0, 0)",
      "ntp_background": "rgb(26, 26, 26)",
      "ntp_text": "rgb(153, 153, 153)",
      "popup_highlight": "rgb(26, 26, 26)",
      "toolbar_field_border_focus": "rgb(26, 26, 26)",
      "toolbar_field_border": "rgb(26, 26, 26)",
      "toolbar_field_separator": "rgb(15, 15, 15)",
      "tab_loading": "rgb(26, 26, 26)"
    }
  }
}