Added base files

Assets/Scripts/_Test/CustomPP/PsudoLensFlare.meta

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Assets/Scripts/_Test/CustomPP/PsudoLensFlare/PseudoFlareVolume.cs

+using System;
+using UnityEngine;
+using UnityEngine.Rendering;
+
+[Serializable, VolumeComponentMenu("Custom/Pseudo Lensflare")]
+public class PseudoFlareVolume : VolumeComponent
+{
+    [Range(0f, 1f), Tooltip("Grayscale effect intensity")]
+    public FloatParameter blend = new FloatParameter(0.5f);
+}

Assets/Scripts/_Test/CustomPP/PsudoLensFlare/PseudoFlareVolume.cs.meta

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Assets/Scripts/_Test/CustomPP/PsudoLensFlare/PseudoLensflareFeature.cs

+using UnityEngine;
+using UnityEngine.Rendering;
+using UnityEngine.Rendering.Universal;
+
+public class PseudoLensflareFeature : ScriptableRendererFeature
+{
+    class PseudoLensflarePass : ScriptableRenderPass
+    {
+        public Material blitMaterial;
+        private PseudoFlareVolume component { get; set; }
+        private RenderTargetIdentifier source { get; set; }
+        private RenderTargetHandle destination { get; set; }
+        
+        string m_ProfilerTag;
+
+        public PseudoLensflarePass(Material blitMaterial)
+        {
+            this.blitMaterial = blitMaterial;
+            renderPassEvent = RenderPassEvent.AfterRenderingPostProcessing;
+            m_ProfilerTag = "Grayscale";
+        }
+
+        public void Setup(RenderTargetIdentifier source, RenderTargetHandle destination, PseudoFlareVolume component)
+        {
+            this.component = component;
+            this.source = source;
+            this.destination = destination;
+        }
+        
+        public override void Execute(ScriptableRenderContext context, ref RenderingData renderingData)
+        {
+            if (component == null || !component.active) return;
+            
+            blitMaterial.SetFloat(Blend, component.blend.value);
+            
+            CommandBuffer cmd = CommandBufferPool.Get(m_ProfilerTag);
+
+            RenderTextureDescriptor opaqueDesc = renderingData.cameraData.cameraTargetDescriptor;
+            opaqueDesc.depthBufferBits = 0;
+
+            Blit(cmd, source, destination.Identifier(), blitMaterial);
+
+            context.ExecuteCommandBuffer(cmd);
+            CommandBufferPool.Release(cmd);
+        }
+    }
+    
+    public Material blitMaterial;
+    PseudoLensflarePass _blitPass;
+    private static readonly int Blend = Shader.PropertyToID("_Blend");
+
+    public override void Create()
+    {
+        _blitPass = new PseudoLensflarePass(blitMaterial);
+    }
+
+    public override void AddRenderPasses(ScriptableRenderer renderer, ref RenderingData renderingData)
+    {
+        var component = VolumeManager.instance.stack.GetComponent<PseudoFlareVolume>();
+        if (component == null || !component.active) return;
+        
+        if (blitMaterial == null)
+        {
+            Debug.LogWarningFormat("Missing Blit Material. {0} blit pass will not execute. Check for missing reference in the assigned renderer.", GetType().Name);
+            return;
+        }
+        
+        var src = renderer.cameraColorTarget;
+        var dest = RenderTargetHandle.CameraTarget;
+        
+        _blitPass.Setup(src, dest, component);
+        renderer.EnqueuePass(_blitPass);
+    }
+}

Assets/Scripts/_Test/CustomPP/PsudoLensFlare/PseudoLensflareFeature.cs.meta

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Assets/Scripts/_Test/CustomPP/PsudoLensFlare/PsudoLenflare.shader

+Shader "Hidden/PostFX/PseudoLensFlare"
+{
+    Properties
+    {
+        _MainTex ("Texture", 2D) = "white" {}
+    }
+    HLSLINCLUDE
+    
+    #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"
+    
+    TEXTURE2D(_MainTex); SAMPLER(sampler_MainTex);
+    float _Blend;
+    
+    struct Attributes
+    {
+        float3 vertex : POSITION;
+    };
+    
+    struct Varyings
+    {
+        float4 vertex : SV_POSITION;
+        float2 texcoord : TEXCOORD0;
+    };
+    
+    float4 Frag(Varyings i) : SV_Target
+    {
+    float4 color = SAMPLE_TEXTURE2D(_MainTex, sampler_MainTex, i.texcoord);
+    float luminance = dot(color.rgb, float3(0.2126729, 0.7151522, 0.0721750));
+    color.rgb = lerp(color.rgb, luminance.xxx, _Blend.xxx);
+    return color;
+    }
+    
+    ENDHLSL
+    
+    SubShader
+    {
+        Cull Off ZWrite Off ZTest Always
+        
+        Pass
+        {
+            HLSLPROGRAM
+            
+            #pragma vertex VertDefault
+            #pragma fragment Frag
+            
+            Varyings VertDefault(Attributes v)
+            {
+                Varyings o;
+                o.vertex = float4(v.vertex.xy * 2.0 - 1.0, 0.0, 1.0);
+                o.texcoord = v.vertex.xy;
+                return o;
+            }
+            
+            ENDHLSL
+        }
+    }
+}

Assets/Scripts/_Test/CustomPP/PsudoLensFlare/PsudoLenflare.shader.meta

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