https://learn.microsoft.com/de-de/dotnet/api/system.windows.markup.xmlnsdictionary?view=netframework-4.8.1&viewFallbackFrom=net-10.0
XmlnsDictionary Class (System.Windows.Markup) | Microsoft Learn
Represents a dictionary that contains xmlns mappings for XAML namespaces in WPF.
class systemwindowsmarkupmicrosoftlearn