TilemapRendererExtension.cs

using UnityEngine.Tilemaps;
using BlendModes;

[ExtendedComponent(typeof(TilemapRenderer))]
public class TilemapRendererExtension : RendererExtension<TilemapRenderer>
{
    public override string[] GetSupportedShaderFamilies ()
    {
        return new[] {
            "SpritesDefault"
        };
    }

    protected override string GetDefaultShaderName ()
    {
        return "Sprites/Default";
    }
}