diff --git a/src/Umbraco.Core/IEmailSender.cs b/src/Umbraco.Abstractions/IEmailSender.cs
similarity index 100%
rename from src/Umbraco.Core/IEmailSender.cs
rename to src/Umbraco.Abstractions/IEmailSender.cs
diff --git a/src/Umbraco.Core/IMainDom.cs b/src/Umbraco.Abstractions/IMainDom.cs
similarity index 100%
rename from src/Umbraco.Core/IMainDom.cs
rename to src/Umbraco.Abstractions/IMainDom.cs
diff --git a/src/Umbraco.Core/LambdaExpressionCacheKey.cs b/src/Umbraco.Abstractions/LambdaExpressionCacheKey.cs
similarity index 98%
rename from src/Umbraco.Core/LambdaExpressionCacheKey.cs
rename to src/Umbraco.Abstractions/LambdaExpressionCacheKey.cs
index 52ec786a6d..c191732acc 100644
--- a/src/Umbraco.Core/LambdaExpressionCacheKey.cs
+++ b/src/Umbraco.Abstractions/LambdaExpressionCacheKey.cs
@@ -9,7 +9,7 @@ namespace Umbraco.Core
     /// Represents a simple <see cref="LambdaExpression"/> in a form which is suitable for using as a dictionary key
     /// by exposing the return type, argument types and expression string form in a single concatenated string.
     /// </summary>
-    internal struct LambdaExpressionCacheKey
+    public struct LambdaExpressionCacheKey
     {
         public LambdaExpressionCacheKey(string returnType, string expression, params string[] argTypes)
         {
diff --git a/src/Umbraco.Core/MonitorLock.cs b/src/Umbraco.Abstractions/MonitorLock.cs
similarity index 100%
rename from src/Umbraco.Core/MonitorLock.cs
rename to src/Umbraco.Abstractions/MonitorLock.cs
diff --git a/src/Umbraco.Core/Umbraco.Core.csproj b/src/Umbraco.Core/Umbraco.Core.csproj
index f400595e81..00d64f4649 100755
--- a/src/Umbraco.Core/Umbraco.Core.csproj
+++ b/src/Umbraco.Core/Umbraco.Core.csproj
@@ -326,7 +326,6 @@
     <Compile Include="Events\ExportedMemberEventArgs.cs" />
     <Compile Include="Events\RolesEventArgs.cs" />
     <Compile Include="Events\UserGroupWithUsers.cs" />
-    <Compile Include="IMainDom.cs" />
     <Compile Include="IO\IFileSystems.cs" />
     <Compile Include="IO\IMediaFileSystem.cs" />
     <Compile Include="GuidUtils.cs" />
@@ -620,7 +619,6 @@
     <Compile Include="HashGenerator.cs" />
     <Compile Include="HttpContextExtensions.cs" />
     <Compile Include="IDisposeOnRequestEnd.cs" />
-    <Compile Include="IEmailSender.cs" />
     <Compile Include="IntExtensions.cs" />
     <Compile Include="IO\FileSecurityException.cs" />
     <Compile Include="IO\FileSystemExtensions.cs" />
@@ -638,7 +636,6 @@
     <Compile Include="IO\ViewHelper.cs" />
     <Compile Include="IRuntime.cs" />
     <Compile Include="IRuntimeState.cs" />
-    <Compile Include="LambdaExpressionCacheKey.cs" />
     <Compile Include="Logging\DebugDiagnosticsLogger.cs" />
     <Compile Include="Logging\Serilog\SerilogLogger.cs" />
     <Compile Include="Logging\LoggingTaskExtension.cs" />
@@ -868,7 +865,6 @@
     <Compile Include="Models\ObjectTypes.cs" />
     <Compile Include="Models\UserExtensions.cs" />
     <Compile Include="Models\Validation\RequiredForPersistenceAttribute.cs" />
-    <Compile Include="MonitorLock.cs" />
     <Compile Include="NamedUdiRange.cs" />
     <Compile Include="NameValueCollectionExtensions.cs" />
     <Compile Include="NetworkHelper.cs" />