Examine source code of vega-red-dark

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "red-dark",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-000-5672c42860d5b06e1058dc477397f3ef.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(36, 26, 26)",
      "toolbar_text": "rgb(255, 73, 73)",
      "frame": "rgb(13, 3, 3)",
      "tab_background_text": "rgb(255, 73, 73)",
      "toolbar_field": "rgba(4, 4, 4, 0.95)",
      "toolbar_field_text": "rgb(255, 73, 73)",
      "tab_line": "rgb(255, 73, 73)",
      "popup": "rgba(14, 8, 8, 0.8)",
      "popup_text": "rgb(255, 73, 73)",
      "ntp_background": "rgb(49, 41, 41)",
      "ntp_text": "rgb(255, 73, 73)",
      "popup_border": "rgb(255, 73, 73)",
      "popup_highlight_text": "rgb(255, 73, 73)",
      "popup_highlight": "rgb(187, 92, 92)",
      "sidebar_highlight_text": "rgb(162, 25, 25)",
      "sidebar_text": "rgb(255, 73, 73)",
      "tab_text": "rgb(255, 73, 73)",
      "toolbar_field_border_focus": "rgb(255, 73, 73)",
      "toolbar_field_border": "rgb(132, 72, 72)",
      "toolbar_field_highlight_text": "rgb(147, 8, 8)",
      "toolbar_field_highlight": "rgb(255, 73, 73)",
      "toolbar_field_text_focus": "rgb(255, 73, 73)",
      "toolbar_vertical_separator": "rgb(252, 54, 54)",
      "tab_loading": "rgb(255, 73, 73)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{911ef461-dce7-4469-9d5c-bf7376a50ed4}"
    }
  }
}