Code for creating icons - wpf

Question

This question is probably stupid but I have googled for some time now and didn't find any answers.
I found a post about button styles in where someone added this code example:
<Style TargetType="{x:Type Button}">
<Setter Property="Background" Value="#373737" />
<Setter Property="Foreground" Value="White" />
<Setter Property="FontSize" Value="15" />
<Setter Property="SnapsToDevicePixels" Value="True" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type Button}">
<Border CornerRadius="4" Background="{TemplateBinding Background}">
<Grid>
<Path x:Name="PathIcon" Width="15" Height="25" Stretch="Fill" Fill="#4C87B3" HorizontalAlignment="Left" Margin="17,0,0,0" Data="F1 M 30.0833,22.1667L 50.6665,37.6043L 50.6665,38.7918L 30.0833,53.8333L 30.0833,22.1667 Z "/>
<ContentPresenter x:Name="MyContentPresenter" Content="{TemplateBinding Content}" HorizontalAlignment="Center" VerticalAlignment="Center" Margin="0,0,0,0" />
</Grid>
</Border>
<ControlTemplate.Triggers>
<Trigger Property="IsMouseOver" Value="True">
<Setter Property="Background" Value="#E59400" />
<Setter Property="Foreground" Value="White" />
<Setter TargetName="PathIcon" Property="Fill" Value="Black" />
</Trigger>
<Trigger Property="IsPressed" Value="True">
<Setter Property="Background" Value="OrangeRed" />
<Setter Property="Foreground" Value="White" />
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
This creates a button with an arrow on the left side of the button.
My question is: How is this data called?
Data="F1 M 30.0833,22.1667L 50.6665,37.6043L 50.6665,38.7918L 30.0833,53.8333L 30.0833,22.1667 Z "
EDIT:
I tried to export some icons. Sometimes I get usable Path.Data and sometimes I get something like this:
<!-- Created with Ai->XAML Export Plug-In Version 0.2 (PC/64) -->
<!-- By Mike Swanson (http://blog.mikeswanson.com/) -->
<Viewbox Width="111.000" Height="81.000"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<Canvas Width="111.000" Height="81.000">
</Canvas>
</Viewbox>
Can I even use this and how?