WpfAnimatedGif: ImageBehavior.AnimatedSource does not exist

I've tried to use WpfAnimatedGif in a new WPF project
https://github.com/XamlAnimatedGif/WpfAnimatedGif

But get the error message
error MC3072: The property 'ImageBehavior.AnimatedSource' does not exist in XML namespace 'http://wpfanimatedgif.codeplex.com'.

Proposed solutions from

• https://github.com/XamlAnimatedGif/WpfAnimatedGif/issues/19 and
• https://github.com/XamlAnimatedGif/WpfAnimatedGif/issues/77

don't seem to help:

I have installed the package from Nuget (tried versions 2.2.0, 1.2.3 and 1.1.10), and git.exe is in my global path. The project is inside a local git repo.

Anyone having any idea what the root cause could be?

MainWindow.xaml:

<Window x:Class="GifWpfTest.MainWindow"        xmlns=http://schemas.microsoft.com/winfx/2006/xaml/presentation        xmlns:d=http://schemas.microsoft.com/expression/blend/2008        xmlns:x=http://schemas.microsoft.com/winfx/2006/xaml        xmlns:mc=http://schemas.openxmlformats.org/markup-compatibility/2006        xmlns:gif=http://wpfanimatedgif.codeplex.com        mc:Ignorable="d"        Title="MainWindow" Height="450" Width="800"><Grid><Image gif:ImageBehavior.AnimatedSource="gif.gif" /></Grid></Window>

Csproj file:

<Project Sdk="Microsoft.NET.Sdk"><PropertyGroup><OutputType>WinExe</OutputType><TargetFramework>net6.0-windows7.0</TargetFramework><Nullable>enable</Nullable><ImplicitUsings>enable</ImplicitUsings><UseWPF>true</UseWPF></PropertyGroup><ItemGroup><PackageReference Include="XamlAnimatedGif" Version="2.2.0" /></ItemGroup><ItemGroup><None Update="gif.gif"><CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory></None></ItemGroup></Project>