maui-linux/Xamarin.Forms.Platform.WPF/Themes/FormsPathIcon.xaml

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                    xmlns:controls="clr-namespace:Xamarin.Forms.Platform.WPF.Controls">

    <Style TargetType="controls:FormsPathIcon">
        <Setter Property="HorizontalAlignment" Value="Stretch"/>
        <Setter Property="VerticalAlignment" Value="Stretch"/>
        <Setter Property="FocusVisualStyle" Value="{x:Null}"/>
        <Setter Property="Height" Value="24"/>
        <Setter Property="Width" Value="24"/>
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="controls:FormsPathIcon">
                    <Viewbox>
                        <Path Data="{Binding Data, RelativeSource={RelativeSource Mode=TemplatedParent}}" 
                          Fill="{TemplateBinding Foreground}"
                          Stretch="Fill" />
                    </Viewbox>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>

</ResourceDictionary>