Examine source code of GitHub Dark Theme

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "GitHub Dark Theme",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-000-5672c42860d5b06e1058dc477397f3ef.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(33, 38, 45)",
      "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": "rgba(35, 205, 179, 0)",
      "popup": "rgb(33, 38, 45)",
      "popup_text": "rgb(255, 255, 255)",
      "popup_border": "rgb(0, 0, 0)",
      "popup_highlight": "rgb(58, 62, 64)",
      "tab_loading": "rgba(35, 205, 179, 0)",
      "toolbar_field_border_focus": "rgb(0, 48, 135)",
      "toolbar_field_highlight": "rgb(0, 56, 154)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{2ca0b5e5-356d-48ab-a0ab-a70b3396fb69}"
    }
  }
}