AngleSharp by Florian Rappl

<PackageReference Include="AngleSharp" Version="0.3.4" />

.NET API 521,216 bytes

 HTMLOptGroupElement

public sealed class HTMLOptGroupElement : HTMLElement
Represents the HTML optgroup element.
namespace AngleSharp.DOM.Html { [DOM("HTMLOptGroupElement")] public sealed class HTMLOptGroupElement : HTMLElement { [DOM("label")] public string Label { get { return GetAttribute("label"); } set { SetAttribute("label", value); } } [DOM("disabled")] public bool Disabled { get { return GetAttribute("disabled") != null; } set { SetAttribute("disabled", value ? string.Empty : null); } } protected internal override bool IsSpecial => false; internal HTMLOptGroupElement() { _name = "optgroup"; } } }