Examine source code of Prone Dark Mode

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Custom Dark Mode",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-000-5672c42860d5b06e1058dc477397f3ef.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(16, 16, 16)",
      "toolbar_text": "rgba(255, 255, 255, 0.93)",
      "frame": "rgb(16, 16, 16)",
      "tab_background_text": "rgb(142, 142, 142)",
      "toolbar_field": "rgb(16, 16, 16)",
      "toolbar_field_text": "rgb(206, 206, 206)",
      "tab_line": "rgba(0, 0, 0, 0)",
      "popup": "rgba(16, 16, 16, 0.81)",
      "popup_text": "rgb(191, 191, 191)",
      "icons_attention": "rgb(143, 41, 255)",
      "icons": "rgb(125, 125, 125)",
      "ntp_background": "rgb(16, 16, 16)",
      "ntp_text": "rgb(255, 255, 255)",
      "toolbar_bottom_separator": "rgba(255, 0, 0, 0)",
      "toolbar_field_border_focus": "rgb(121, 0, 255)",
      "toolbar_field_focus": "rgba(16, 16, 16, 0.5)",
      "toolbar_field_highlight": "rgb(121, 0, 255)",
      "toolbar_top_separator": "rgba(255, 0, 0, 0)",
      "tab_loading": "rgba(0, 0, 0, 0)"
    }
  }
}