Surface shader custom lighting model in deferred lighting

I have a custom lighting model that is working as expected in forward rendering. Following the documentation at https://docs.unity3d.com/Manual/SL-SurfaceShaderLighting.html I attempted to support deferred by adding a (...)_PrePass function. It did not appear to be working, so I scaled back to a basic example.

I am sure that I the project/camera is set to deferred because e.g. the frame debugger shows other objects using the standard shader drawing as you would expect in the RenderDeferred.x steps.

For example, following http://kylehalladay.com/blog/tutorial/2014/04/05/Writing-Shaders-For-Deferred-Lighting-Unity.html . That shader does not work either - it does not render anything.

Has anything changed in how this works? Here is the body of the example shader:

 Shader "Custom/DeferredDiffuse"
 {
     Properties
     {
         _MainTex("Base (RGB)", 2D) = "white" {}
     }
         SubShader
     {
         Tags{ "RenderType" = "Opaque" }
         LOD 200
 
         CGPROGRAM
 #pragma surface surf MyDiffuse
 
         sampler2D _MainTex;
 
     struct Input {
         float2 uv_MainTex;
     };
 
     void surf(Input IN, inout SurfaceOutput o) {
         half4 c = tex2D(_MainTex, IN.uv_MainTex);
         o.Albedo = c.rgb;
         o.Alpha = c.a;
     }
 
     float4 LightingMyDiffuse_PrePass(SurfaceOutput i, float4 light)
     {
         return float4(i.Albedo * light.rgb, 1.0);
     }
     ENDCG
     }
 }