diff --git a/eng/Subsets.props b/eng/Subsets.props
index d412c83ae09f12..a1c0836392f6f9 100644
--- a/eng/Subsets.props
+++ b/eng/Subsets.props
@@ -196,8 +196,6 @@
     <SubsetName Include="Libs.Native" Description="The native libraries used in the shared framework." />
     <SubsetName Include="Libs.Sfx" Description="The managed shared framework libraries." />
     <SubsetName Include="Libs.Oob" Description="The managed out-of-band libraries." />
-    <SubsetName Include="Libs.Ref" OnDemand="true" Description="The managed reference libraries." />
-    <SubsetName Include="Libs.Src" OnDemand="true" Description="The managed implementation libraries." />
     <SubsetName Include="Libs.PreTest" Description="Test assets which are necessary to run tests." />
     <SubsetName Include="Libs.Tests" OnDemand="true" Description="The test projects. Note that building this doesn't execute tests: you must also pass the '-test' argument." />
 
@@ -481,20 +479,16 @@
     <ProjectToBuild Include="$(SharedNativeRoot)libs\build-native.proj" Category="libs" />
   </ItemGroup>
 
-  <ItemGroup Condition="$(_subset.Contains('+libs.ref+')) or $(_subset.Contains('+libs.src+')) or $(_subset.Contains('+libs.sfx+'))">
+  <ItemGroup Condition="$(_subset.Contains('+libs.sfx+'))">
     <ProjectToBuild Include="$(LibrariesProjectRoot)sfx.proj"
                     Category="libs"
                     Condition="'$(BuildTargetFramework)' == '$(NetCoreAppCurrent)' or
                                '$(BuildTargetFramework)' == '' or
-                               '$(BuildAllConfigurations)' == 'true'">
-      <AdditionalProperties Condition="$(_subset.Contains('+libs.ref+'))">%(AdditionalProperties);RefOnly=true</AdditionalProperties>
-    </ProjectToBuild>
+                               '$(BuildAllConfigurations)' == 'true'" />
   </ItemGroup>
 
-  <ItemGroup Condition="$(_subset.Contains('+libs.ref+')) or $(_subset.Contains('+libs.src+')) or $(_subset.Contains('+libs.oob+'))">
-    <ProjectToBuild Include="$(LibrariesProjectRoot)oob.proj" Category="libs">
-      <AdditionalProperties Condition="$(_subset.Contains('+libs.ref+'))">%(AdditionalProperties);RefOnly=true</AdditionalProperties>
-    </ProjectToBuild>
+  <ItemGroup Condition="$(_subset.Contains('+libs.oob+'))">
+    <ProjectToBuild Include="$(LibrariesProjectRoot)oob.proj" Category="libs" />
   </ItemGroup>
 
   <ItemGroup Condition="$(_subset.Contains('+mono.wasmruntime+'))">
diff --git a/src/libraries/oob.proj b/src/libraries/oob.proj
index 21db8f35584f19..96cddf78dc877a 100644
--- a/src/libraries/oob.proj
+++ b/src/libraries/oob.proj
@@ -22,13 +22,6 @@
     <ProjectReference Include="oob-gen.proj" Condition="'$(DotNetBuildSourceOnly)' != 'true'" />
   </ItemGroup>
 
-  <!-- Support building reference projects only. -->
-  <ItemGroup Condition="'$(RefOnly)' == 'true'">
-    <ProjectReference Remove="@(ProjectReference)" />
-    <ProjectReference Include="sfx-ref.proj" OutputItemType="SharedFrameworkAssembly" />
-    <ProjectReference Include="oob-ref.proj" />
-  </ItemGroup>
-
   <Target Name="GetTrimOOBAssembliesInputs"
           DependsOnTargets="ResolveProjectReferences">
     <PropertyGroup>
@@ -47,7 +40,7 @@
 
   <Target Name="TrimOOBAssemblies"
           AfterTargets="Build"
-          Condition="'$(RefOnly)' != 'true' and '@(OOBAssembly)' != ''"
+          Condition="'@(OOBAssembly)' != ''"
           DependsOnTargets="GetTrimOOBAssembliesInputs;PrepareForAssembliesTrim"
           Inputs="$(ILLinkTasksAssembly);@(OOBAssemblyToTrim);@(OOBAssemblyReference);@(OOBLibrarySuppressionsXml)"
           Outputs="$(OOBAssembliesTrimMarkerFile)">
diff --git a/src/libraries/sfx-ref.proj b/src/libraries/sfx-ref.proj
index 57bec669a2f3d7..b1a3916acf4e18 100644
--- a/src/libraries/sfx-ref.proj
+++ b/src/libraries/sfx-ref.proj
@@ -17,12 +17,4 @@
                                System.Private.CoreLib\ref\System.Private.CoreLib.csproj" />
   </ItemGroup>
 
-  <ItemGroup Condition="'$(RefOnly)' == 'true'">
-    <ProjectReference Include="shims\*\src\*.csproj" />
-    <ReferenceShimProject Include="shims\*\ref\*.csproj" />
-    <ProjectReference Include="@(ReferenceShimProject)" />
-    <!-- Omit projects which depend on source projects to be built. -->
-    <ProjectReference Remove="@(ReferenceShimProject->'shims\%(Filename)\src\%(Filename)%(Extension)')" />
-  </ItemGroup>
-
 </Project>
diff --git a/src/libraries/sfx.proj b/src/libraries/sfx.proj
index 9b174d57c90f0a..4a09c525dfae47 100644
--- a/src/libraries/sfx.proj
+++ b/src/libraries/sfx.proj
@@ -14,11 +14,8 @@
   <ItemGroup>
     <!-- The sfx ref projects must be built first as sfx src projects don't use P2Ps to reference each other. Instead the
          references are defined manually via Reference items, therefore the reference assemblies must exist before that. -->
-    <ProjectReference Include="sfx-ref.proj">
-      <OutputItemType Condition="'$(RefOnly)' == 'true'">SharedFrameworkAssembly</OutputItemType>
-    </ProjectReference>
-     <!-- The RefOnly condition exists to support building the reference source projects only. -->
-    <ProjectReference Include="sfx-src.proj" OutputItemType="SharedFrameworkAssembly" Condition="'$(RefOnly)' != 'true'" />
+    <ProjectReference Include="sfx-ref.proj" />
+    <ProjectReference Include="sfx-src.proj" OutputItemType="SharedFrameworkAssembly" />
     <ProjectReference Include="sfx-gen.proj" OutputItemType="SharedFrameworkAnalyzerAssembly" />
   </ItemGroup>
 
@@ -61,8 +58,7 @@
 
   <!-- Copy the intellisense file to the targeting pack directory. -->
   <Target Name="CopyDocumentationFiles"
-          AfterTargets="Build"
-          Condition="'$(RefOnly)' != 'true'">
+          AfterTargets="Build">
     <ItemGroup>
       <DocumentationFileToCopy Include="@(SharedFrameworkAssembly->WithMetadataValue('IsPrivateAssembly', 'false')->Metadata('DocFileItem'))" />
     </ItemGroup>
@@ -89,7 +85,6 @@
   <Target Name="TrimSharedFrameworkAssemblies"
           AfterTargets="Build"
           DependsOnTargets="ResolveProjectReferences;GetTrimSharedFrameworkAssembliesInputs;PrepareForAssembliesTrim"
-          Condition="'$(RefOnly)' != 'true'"
           Inputs="@(SharedFrameworkAssembly);@(SharedFrameworkSuppressionsXml);$(ILLinkTasksAssembly)"
           Outputs="$(SharedFrameworkAssembliesTrimMarkerFile)">
     <Message Text="$(MSBuildProjectName) -> Trimming $(OutputRID) shared framework assemblies with ILLinker..." Importance="high" />