https://learn.microsoft.com/en-us/uwp/api/windows.ui.xaml.controls.inktoolbarcustompenbutton?view=winrt-28000&redirectedfrom=MSDN
InkToolbarCustomPenButton Class (Windows.UI.Xaml.Controls) - Windows apps | Microsoft Learn
Represents an InkToolbar button that activates a pen for which the ink color palette and pen tip properties, such as shape, rotation, and size, are defined by...
classwindowsuixamlcontrols
https://learn.microsoft.com/en-us/uwp/api/windows.ui.xaml.controls.inktoolbarcustompenbutton.configurationcontent?view=winrt-28000
InkToolbarCustomPenButton.ConfigurationContent Property (Windows.UI.Xaml.Controls) - Windows apps |...
Gets or sets the content of an optional ink stroke configuration flyout associated with the InkToolbarCustomPenButton.
propertywindowsuixamlcontrols