Avalonia/src/Avalonia.Base/Metadata/UnstableAttribute.cs

using System;

namespace Avalonia.Metadata
{
    /// <summary>
    /// This API is unstable and is not covered by API compatibility guarantees between minor and
    /// patch releases.
    /// </summary>
    [AttributeUsage(AttributeTargets.All)]
    public sealed class UnstableAttribute : Attribute
    {
    }
}