public static readonly HtmlParser DefaultHtmlParser

The default HtmlParser has HtmlParserOptions.IsNotConsumingCharacterReferences set to true so that character references are not decoded when parsing (which is important for passing encoded characters like @ through to engines like Razor that require them to be encoded if literal). This has the unfortunate side effect of triggering double-encoding on serialization, see https://github.com/AngleSharp/AngleSharp/issues/396#issuecomment-246106539. To avoid that, use StatiqMarkupFormatter or one of the extensions from IMarkupFormattableExtensions or IElementExtensions whenever serialization needs to be performed from a IHtmlDocument obtained from this method.