[wasm] Docs on overriding runtime pack in blazor wasm (#85455)

diff --git a/src/mono/wasm/build/README.md b/src/mono/wasm/build/README.md
index e9552c8..e1565c8 100644 (file)
--- a/src/mono/wasm/build/README.md
+++ b/src/mono/wasm/build/README.md
@@ -140,4 +140,17 @@ If encountering build performance issues, you can use the rollup `--perf` option
 
 ```node node_modules/typescript/lib/tsc.js --generateCpuProfile dotnet-tsc.cpuprofile -p tsconfig.json ```
 
-The .cpuprofile file generated by node can be opened in the Performance tab of Chrome or Edge's devtools.
\ No newline at end of file
+The .cpuprofile file generated by node can be opened in the Performance tab of Chrome or Edge's devtools.
+
+## Blazor
+
+You can test local build of runtime in blazor by overriding location where blazor resolves runtime pack from
+
+*BlazorWasm.csproj*
+```xml
+<Target Name="UpdateRuntimePack" AfterTargets="ResolveFrameworkReferences">
+  <ItemGroup>
+    <ResolvedRuntimePack PackageDirectory="{RUNTIME_REPO_ROOT}\artifacts\bin\microsoft.netcore.app.runtime.browser-wasm\Debug" Condition="'%(ResolvedRuntimePack.FrameworkName)' == 'Microsoft.NETCore.App'" />
+  </ItemGroup>
+</Target>
+```
\ No newline at end of file