https://learn.microsoft.com/en-us/dotnet/api/system.windows.frameworkcontentelement.defaultstylekey?view=netframework-4.8.1&viewFallbackFrom=windowsdesktop-10.0
FrameworkContentElement.DefaultStyleKey Property (System.Windows) | Microsoft Learn
Gets or sets the key to use to find the style template for this control in themes.
property systemwindowsmicrosoftlearn