Placeholder shader includes.

MaterialGraphProject/Assets/UnityShaderEditor/Editor/DefaultShaderIncludes.cs

+namespace UnityEditor
+{
+    internal static class DefaultShaderIncludes
+    {
+        [ShaderIncludePath]
+        public static string[] GetPaths()
+        {
+            return new[]
+            {
+                "Assets/ScriptableRenderPipeline/",
+                "Assets/SRP/ScriptableRenderPipeline/LightweightPipeline/Shaders"
+            };
+        }
+    }
+}

MaterialGraphProject/Assets/UnityShaderEditor/Editor/DefaultShaderIncludes.cs.meta

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