diff --git a/src/client/Microsoft.Identity.Client/ApiConfig/AcquireTokenByAuthorizationCodeParameterBuilder.cs b/src/client/Microsoft.Identity.Client/ApiConfig/AcquireTokenByAuthorizationCodeParameterBuilder.cs
index 5f7c44b469..5846ea5faf 100644
--- a/src/client/Microsoft.Identity.Client/ApiConfig/AcquireTokenByAuthorizationCodeParameterBuilder.cs
+++ b/src/client/Microsoft.Identity.Client/ApiConfig/AcquireTokenByAuthorizationCodeParameterBuilder.cs
@@ -5,7 +5,7 @@
 using System.Collections.Generic;
 using System.Threading;
 using System.Threading.Tasks;
-using Microsoft.Identity.Client.Advanced;
+using Microsoft.Identity.Client.Extensibility;
 using Microsoft.Identity.Client.ApiConfig.Executors;
 using Microsoft.Identity.Client.ApiConfig.Parameters;
 using Microsoft.Identity.Client.Internal;
diff --git a/src/client/Microsoft.Identity.Client/ApiConfig/AcquireTokenOnBehalfOfParameterBuilder.cs b/src/client/Microsoft.Identity.Client/ApiConfig/AcquireTokenOnBehalfOfParameterBuilder.cs
index 4589d3079b..d52e68e998 100644
--- a/src/client/Microsoft.Identity.Client/ApiConfig/AcquireTokenOnBehalfOfParameterBuilder.cs
+++ b/src/client/Microsoft.Identity.Client/ApiConfig/AcquireTokenOnBehalfOfParameterBuilder.cs
@@ -1,87 +1,87 @@
-// Copyright (c) Microsoft Corporation. All rights reserved.
-// Licensed under the MIT License.
-
-using System;
-using System.Collections.Generic;
-using System.Threading;
-using System.Threading.Tasks;
-using Microsoft.Identity.Client.Advanced;
-using Microsoft.Identity.Client.ApiConfig.Executors;
-using Microsoft.Identity.Client.ApiConfig.Parameters;
-using Microsoft.Identity.Client.Internal;
-using Microsoft.Identity.Client.TelemetryCore.Internal.Events;
-using Microsoft.Identity.Client.Utils;
-
-namespace Microsoft.Identity.Client
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+using System;
+using System.Collections.Generic;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.Identity.Client.Extensibility;
+using Microsoft.Identity.Client.ApiConfig.Executors;
+using Microsoft.Identity.Client.ApiConfig.Parameters;
+using Microsoft.Identity.Client.Internal;
+using Microsoft.Identity.Client.TelemetryCore.Internal.Events;
+using Microsoft.Identity.Client.Utils;
+
+namespace Microsoft.Identity.Client
 {
-    /// <summary>
-    /// Builder for AcquireTokenOnBehalfOf (OBO flow)
-    /// See https://aka.ms/msal-net-on-behalf-of
-    /// </summary>
-#if !SUPPORTS_CONFIDENTIAL_CLIENT
-    [System.ComponentModel.EditorBrowsable(System.ComponentModel.EditorBrowsableState.Never)]  // hide confidential client on mobile
-#endif
-    public sealed class AcquireTokenOnBehalfOfParameterBuilder :
-        AbstractConfidentialClientAcquireTokenParameterBuilder<AcquireTokenOnBehalfOfParameterBuilder>
-    {
-        internal AcquireTokenOnBehalfOfParameters Parameters { get; } = new AcquireTokenOnBehalfOfParameters();
-
-        /// <inheritdoc/>
-        internal AcquireTokenOnBehalfOfParameterBuilder(IConfidentialClientApplicationExecutor confidentialClientApplicationExecutor)
-            : base(confidentialClientApplicationExecutor)
-        {
-        }
-
-        internal static AcquireTokenOnBehalfOfParameterBuilder Create(
-            IConfidentialClientApplicationExecutor confidentialClientApplicationExecutor,
-            IEnumerable<string> scopes,
-            UserAssertion userAssertion)
-        {
-            return new AcquireTokenOnBehalfOfParameterBuilder(confidentialClientApplicationExecutor)
-                   .WithScopes(scopes)
-                   .WithUserAssertion(userAssertion);
-        }
-
-        internal static AcquireTokenOnBehalfOfParameterBuilder Create(
-            IConfidentialClientApplicationExecutor confidentialClientApplicationExecutor,
-            IEnumerable<string> scopes,
-            UserAssertion userAssertion,
-            string cacheKey)
-        {
-            return new AcquireTokenOnBehalfOfParameterBuilder(confidentialClientApplicationExecutor)
-                   .WithScopes(scopes)
-                   .WithUserAssertion(userAssertion)
-                   .WithCacheKey(cacheKey);
-        }
-
-        internal static AcquireTokenOnBehalfOfParameterBuilder Create(
-            IConfidentialClientApplicationExecutor confidentialClientApplicationExecutor,
-            IEnumerable<string> scopes,
-            string cacheKey)
-        {
-            return new AcquireTokenOnBehalfOfParameterBuilder(confidentialClientApplicationExecutor)
-                   .WithScopes(scopes)
-                   .WithCacheKey(cacheKey);
-        }
-
-        private AcquireTokenOnBehalfOfParameterBuilder WithUserAssertion(UserAssertion userAssertion)
-        {
-            Parameters.UserAssertion = userAssertion;
-            return this;
-        }
-
-        /// <summary>
-        /// Specifies a key by which to look up the token in the cache instead of searching by an assertion.
-        /// </summary>
-        /// <param name="cacheKey">Key by which to look up the token in the cache</param>
-        /// <returns>A builder enabling you to add optional parameters before executing the token request</returns>
-        private AcquireTokenOnBehalfOfParameterBuilder WithCacheKey(string cacheKey)
-        {
-            Parameters.LongRunningOboCacheKey = cacheKey ?? throw new ArgumentNullException(nameof(cacheKey));
-            return this;
-        }
-
-        /// <summary>
+    /// <summary>
+    /// Builder for AcquireTokenOnBehalfOf (OBO flow)
+    /// See https://aka.ms/msal-net-on-behalf-of
+    /// </summary>
+#if !SUPPORTS_CONFIDENTIAL_CLIENT
+    [System.ComponentModel.EditorBrowsable(System.ComponentModel.EditorBrowsableState.Never)]  // hide confidential client on mobile
+#endif
+    public sealed class AcquireTokenOnBehalfOfParameterBuilder :
+        AbstractConfidentialClientAcquireTokenParameterBuilder<AcquireTokenOnBehalfOfParameterBuilder>
+    {
+        internal AcquireTokenOnBehalfOfParameters Parameters { get; } = new AcquireTokenOnBehalfOfParameters();
+
+        /// <inheritdoc/>
+        internal AcquireTokenOnBehalfOfParameterBuilder(IConfidentialClientApplicationExecutor confidentialClientApplicationExecutor)
+            : base(confidentialClientApplicationExecutor)
+        {
+        }
+
+        internal static AcquireTokenOnBehalfOfParameterBuilder Create(
+            IConfidentialClientApplicationExecutor confidentialClientApplicationExecutor,
+            IEnumerable<string> scopes,
+            UserAssertion userAssertion)
+        {
+            return new AcquireTokenOnBehalfOfParameterBuilder(confidentialClientApplicationExecutor)
+                   .WithScopes(scopes)
+                   .WithUserAssertion(userAssertion);
+        }
+
+        internal static AcquireTokenOnBehalfOfParameterBuilder Create(
+            IConfidentialClientApplicationExecutor confidentialClientApplicationExecutor,
+            IEnumerable<string> scopes,
+            UserAssertion userAssertion,
+            string cacheKey)
+        {
+            return new AcquireTokenOnBehalfOfParameterBuilder(confidentialClientApplicationExecutor)
+                   .WithScopes(scopes)
+                   .WithUserAssertion(userAssertion)
+                   .WithCacheKey(cacheKey);
+        }
+
+        internal static AcquireTokenOnBehalfOfParameterBuilder Create(
+            IConfidentialClientApplicationExecutor confidentialClientApplicationExecutor,
+            IEnumerable<string> scopes,
+            string cacheKey)
+        {
+            return new AcquireTokenOnBehalfOfParameterBuilder(confidentialClientApplicationExecutor)
+                   .WithScopes(scopes)
+                   .WithCacheKey(cacheKey);
+        }
+
+        private AcquireTokenOnBehalfOfParameterBuilder WithUserAssertion(UserAssertion userAssertion)
+        {
+            Parameters.UserAssertion = userAssertion;
+            return this;
+        }
+
+        /// <summary>
+        /// Specifies a key by which to look up the token in the cache instead of searching by an assertion.
+        /// </summary>
+        /// <param name="cacheKey">Key by which to look up the token in the cache</param>
+        /// <returns>A builder enabling you to add optional parameters before executing the token request</returns>
+        private AcquireTokenOnBehalfOfParameterBuilder WithCacheKey(string cacheKey)
+        {
+            Parameters.LongRunningOboCacheKey = cacheKey ?? throw new ArgumentNullException(nameof(cacheKey));
+            return this;
+        }
+
+        /// <summary>
         /// Applicable to first-party applications only, this method also allows to specify 
         /// if the <see href="https://datatracker.ietf.org/doc/html/rfc7517#section-4.7">x5c claim</see> should be sent to Azure AD.
         /// Sending the x5c enables application developers to achieve easy certificate roll-over in Azure AD:
@@ -89,96 +89,96 @@ private AcquireTokenOnBehalfOfParameterBuilder WithCacheKey(string cacheKey)
         /// so that Azure AD can use it to validate the subject name based on a trusted issuer policy.
         /// This saves the application admin from the need to explicitly manage the certificate rollover
         /// (either via portal or PowerShell/CLI operation). For details see https://aka.ms/msal-net-sni
-        /// </summary>
-        /// <param name="withSendX5C"><c>true</c> if the x5c should be sent. Otherwise <c>false</c>.
-        /// The default is <c>false</c></param>
-        /// <returns>The builder to chain the .With methods</returns>
-        public AcquireTokenOnBehalfOfParameterBuilder WithSendX5C(bool withSendX5C)
-        {
+        /// </summary>
+        /// <param name="withSendX5C"><c>true</c> if the x5c should be sent. Otherwise <c>false</c>.
+        /// The default is <c>false</c></param>
+        /// <returns>The builder to chain the .With methods</returns>
+        public AcquireTokenOnBehalfOfParameterBuilder WithSendX5C(bool withSendX5C)
+        {
             Parameters.SendX5C = withSendX5C;
-            return this;
-        }
-
-        /// <summary>
+            return this;
+        }
+
+        /// <summary>
         /// Specifies if the client application should ignore access tokens when reading the token cache. 
         /// New tokens will still be written to the token cache.
         /// By default the token is taken from the the user token cache (forceRefresh=false)
-        /// </summary>
-        /// <param name="forceRefresh">If <c>true</c>, ignore any access token in the user token cache
-        /// and attempt to acquire new access token using the refresh token for the account
+        /// </summary>
+        /// <param name="forceRefresh">If <c>true</c>, ignore any access token in the user token cache
+        /// and attempt to acquire new access token using the refresh token for the account
         /// if one is available. The default is <c>false</c></param>
-        /// <returns>The builder to chain the .With methods</returns>
+        /// <returns>The builder to chain the .With methods</returns>
         /// <remarks>
         /// Do not use this flag except in well understood cases. Identity Providers will throttle clients that issue too many similar token requests.
         /// </remarks>        
-        public AcquireTokenOnBehalfOfParameterBuilder WithForceRefresh(bool forceRefresh)
-        {
-            Parameters.ForceRefresh = forceRefresh;
-            return this;
-        }
-
-        /// <summary>
-        /// To help with resiliency, the AAD backup authentication system operates as an AAD backup.
-        /// This will provide the AAD backup authentication system with a routing hint to help improve performance during authentication.
-        /// </summary>
-        /// <param name="userObjectIdentifier">GUID which is unique to the user, parsed from the client_info.</param>
-        /// <param name="tenantIdentifier">GUID format of the tenant ID, parsed from the client_info.</param>
-        /// <returns>The builder to chain the .With methods</returns>
-        public AcquireTokenOnBehalfOfParameterBuilder WithCcsRoutingHint(string userObjectIdentifier, string tenantIdentifier)
-        {
-            if (string.IsNullOrEmpty(userObjectIdentifier) || string.IsNullOrEmpty(tenantIdentifier))
-            {
-                return this;
-            }
-
-            var ccsRoutingHeader = new Dictionary<string, string>()
-            {
-                { Constants.CcsRoutingHintHeader, CoreHelpers.GetCcsClientInfoHint(userObjectIdentifier, tenantIdentifier) }
-            };
-
-            this.WithExtraHttpHeaders(ccsRoutingHeader);
-            return this;
-        }
-
-        /// <summary>
-        /// To help with resiliency, the AAD backup authentication system operates as an AAD backup.
-        /// This will provide the AAD backup authentication system with a routing hint to help improve performance during authentication.
-        /// </summary>
-        /// <param name="userName">Identifier of the user. Generally in UserPrincipalName (UPN) format, e.g. <c>john.doe@contoso.com</c></param>
-        /// <returns>The builder to chain the .With methods</returns>
-        public AcquireTokenOnBehalfOfParameterBuilder WithCcsRoutingHint(string userName)
-        {
-            if (string.IsNullOrEmpty(userName))
-            {
-                return this;
-            }
-
-            var ccsRoutingHeader = new Dictionary<string, string>()
-            {
-                { Constants.CcsRoutingHintHeader, CoreHelpers.GetCcsUpnHint(userName) }
-            };
-
-            this.WithExtraHttpHeaders(ccsRoutingHeader);
-            return this;
+        public AcquireTokenOnBehalfOfParameterBuilder WithForceRefresh(bool forceRefresh)
+        {
+            Parameters.ForceRefresh = forceRefresh;
+            return this;
+        }
+
+        /// <summary>
+        /// To help with resiliency, the AAD backup authentication system operates as an AAD backup.
+        /// This will provide the AAD backup authentication system with a routing hint to help improve performance during authentication.
+        /// </summary>
+        /// <param name="userObjectIdentifier">GUID which is unique to the user, parsed from the client_info.</param>
+        /// <param name="tenantIdentifier">GUID format of the tenant ID, parsed from the client_info.</param>
+        /// <returns>The builder to chain the .With methods</returns>
+        public AcquireTokenOnBehalfOfParameterBuilder WithCcsRoutingHint(string userObjectIdentifier, string tenantIdentifier)
+        {
+            if (string.IsNullOrEmpty(userObjectIdentifier) || string.IsNullOrEmpty(tenantIdentifier))
+            {
+                return this;
+            }
+
+            var ccsRoutingHeader = new Dictionary<string, string>()
+            {
+                { Constants.CcsRoutingHintHeader, CoreHelpers.GetCcsClientInfoHint(userObjectIdentifier, tenantIdentifier) }
+            };
+
+            this.WithExtraHttpHeaders(ccsRoutingHeader);
+            return this;
+        }
+
+        /// <summary>
+        /// To help with resiliency, the AAD backup authentication system operates as an AAD backup.
+        /// This will provide the AAD backup authentication system with a routing hint to help improve performance during authentication.
+        /// </summary>
+        /// <param name="userName">Identifier of the user. Generally in UserPrincipalName (UPN) format, e.g. <c>john.doe@contoso.com</c></param>
+        /// <returns>The builder to chain the .With methods</returns>
+        public AcquireTokenOnBehalfOfParameterBuilder WithCcsRoutingHint(string userName)
+        {
+            if (string.IsNullOrEmpty(userName))
+            {
+                return this;
+            }
+
+            var ccsRoutingHeader = new Dictionary<string, string>()
+            {
+                { Constants.CcsRoutingHintHeader, CoreHelpers.GetCcsUpnHint(userName) }
+            };
+
+            this.WithExtraHttpHeaders(ccsRoutingHeader);
+            return this;
         }
-
-        /// <inheritdoc/>
-        internal override Task<AuthenticationResult> ExecuteInternalAsync(CancellationToken cancellationToken)
-        {
-            return ConfidentialClientApplicationExecutor.ExecuteAsync(CommonParameters, Parameters, cancellationToken);
-        }
-
+
+        /// <inheritdoc/>
+        internal override Task<AuthenticationResult> ExecuteInternalAsync(CancellationToken cancellationToken)
+        {
+            return ConfidentialClientApplicationExecutor.ExecuteAsync(CommonParameters, Parameters, cancellationToken);
+        }
+
         /// <inheritdoc/>
         protected override void Validate()
         {
             base.Validate();
-            if (Parameters.SendX5C == null)
-            {
-                Parameters.SendX5C = this.ServiceBundle.Config?.SendX5C ?? false;
+            if (Parameters.SendX5C == null)
+            {
+                Parameters.SendX5C = this.ServiceBundle.Config?.SendX5C ?? false;
             }
-        }
-        /// <inheritdoc/>
-        internal override ApiEvent.ApiIds CalculateApiEventId()
+        }
+        /// <inheritdoc/>
+        internal override ApiEvent.ApiIds CalculateApiEventId()
         {
             if (string.IsNullOrEmpty(Parameters.LongRunningOboCacheKey))
             {
@@ -194,7 +194,7 @@ internal override ApiEvent.ApiIds CalculateApiEventId()
                 {
                     return ApiEvent.ApiIds.AcquireTokenInLongRunningObo;
                 }
-            }
-        }
-    }
-}
+            }
+        }
+    }
+}
diff --git a/src/client/Microsoft.Identity.Client/AppConfig/BaseAbstractApplicationBuilder.cs b/src/client/Microsoft.Identity.Client/AppConfig/BaseAbstractApplicationBuilder.cs
index b60ae2dbe0..bf083a6101 100644
--- a/src/client/Microsoft.Identity.Client/AppConfig/BaseAbstractApplicationBuilder.cs
+++ b/src/client/Microsoft.Identity.Client/AppConfig/BaseAbstractApplicationBuilder.cs
@@ -169,6 +169,7 @@ public T WithLogging(
         /// <exception cref="InvalidOperationException"/> is thrown if the loggingCallback
         /// was already set on the application builder by calling <see cref="WithLogging(LogCallback, LogLevel?, bool?, bool?)"/>
         /// <seealso cref="WithLogging(LogCallback, LogLevel?, bool?, bool?)"/>
+        [EditorBrowsable(EditorBrowsableState.Never)]
         public T WithDebugLoggingCallback(
             LogLevel logLevel = LogLevel.Info,
             bool enablePiiLogging = false,
@@ -218,6 +219,7 @@ public T WithExperimentalFeatures(bool enableExperimentalFeatures = true)
         /// </summary>
         /// <param name="clientName">The name of the SDK API for telemetry purposes.</param>
         /// <returns></returns>
+        [EditorBrowsable(EditorBrowsableState.Never)]
         public T WithClientName(string clientName)
         {
             Config.ClientName = GetValueIfNotEmpty(Config.ClientName, clientName);
@@ -229,6 +231,7 @@ public T WithClientName(string clientName)
         /// </summary>
         /// <param name="clientVersion">The version of the calling SDK for telemetry purposes.</param>
         /// <returns></returns>
+        [EditorBrowsable(EditorBrowsableState.Never)]
         public T WithClientVersion(string clientVersion)
         {
             Config.ClientVersion = GetValueIfNotEmpty(Config.ClientVersion, clientVersion);
diff --git a/src/client/Microsoft.Identity.Client/Extensibility/AcquireTokenParameterBuilderExtensions.cs b/src/client/Microsoft.Identity.Client/Extensibility/AcquireTokenParameterBuilderExtensions.cs
index 198b135712..1d318946f8 100644
--- a/src/client/Microsoft.Identity.Client/Extensibility/AcquireTokenParameterBuilderExtensions.cs
+++ b/src/client/Microsoft.Identity.Client/Extensibility/AcquireTokenParameterBuilderExtensions.cs
@@ -3,6 +3,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.ComponentModel;
 
 namespace Microsoft.Identity.Client.Advanced  
 {
@@ -16,13 +17,14 @@ public static class AcquireTokenParameterBuilderExtensions
         /// <param name="builder">Parameter builder for a acquiring tokens.</param>
         /// <param name="extraHttpHeaders">additional Http Headers to add to the token request.</param>
         /// <returns></returns>
+        [EditorBrowsable(EditorBrowsableState.Never)]
+        [Obsolete("This method has been moved to the Microsoft.Identity.Client.Extensibility namespace", false)]
         public static T WithExtraHttpHeaders<T>(
             this AbstractAcquireTokenParameterBuilder<T> builder, 
             IDictionary<string, string> extraHttpHeaders)
             where T : AbstractAcquireTokenParameterBuilder<T>
         {
-            builder.CommonParameters.ExtraHttpHeaders = extraHttpHeaders;
-            return (T)builder;
+            return Microsoft.Identity.Client.Extensibility.AcquireTokenParameterBuilderExtensions.WithExtraHttpHeaders(builder, extraHttpHeaders);
         }
     }
 }
@@ -42,10 +44,9 @@ public static T WithExtraHttpHeaders<T>(
             this AbstractAcquireTokenParameterBuilder<T> builder,
             IDictionary<string, string> extraHttpHeaders)
             where T : AbstractAcquireTokenParameterBuilder<T>
-        {
-            // Delegate to the Advanced implementation to keep a single source of truth.
-            return Advanced.AcquireTokenParameterBuilderExtensions
-                   .WithExtraHttpHeaders(builder, extraHttpHeaders);
+        {            
+            builder.CommonParameters.ExtraHttpHeaders = extraHttpHeaders;
+            return (T)builder;
         }
     }
 }
diff --git a/tests/Microsoft.Identity.Test.Integration.netcore/SeleniumTests/ConfidentialClientAuthorizationTests.cs b/tests/Microsoft.Identity.Test.Integration.netcore/SeleniumTests/ConfidentialClientAuthorizationTests.cs
index 41e4226364..35a9bba068 100644
--- a/tests/Microsoft.Identity.Test.Integration.netcore/SeleniumTests/ConfidentialClientAuthorizationTests.cs
+++ b/tests/Microsoft.Identity.Test.Integration.netcore/SeleniumTests/ConfidentialClientAuthorizationTests.cs
@@ -8,7 +8,7 @@
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.Identity.Client;
-using Microsoft.Identity.Client.Advanced;
+using Microsoft.Identity.Client.Extensibility;
 using Microsoft.Identity.Client.UI;
 using Microsoft.Identity.Test.Common;
 using Microsoft.Identity.Test.Common.Core.Helpers;
diff --git a/tests/Microsoft.Identity.Test.Unit/PublicApiTests/PublicClientApplicationTests.cs b/tests/Microsoft.Identity.Test.Unit/PublicApiTests/PublicClientApplicationTests.cs
index 7cc3cfd0dd..e152def6a5 100644
--- a/tests/Microsoft.Identity.Test.Unit/PublicApiTests/PublicClientApplicationTests.cs
+++ b/tests/Microsoft.Identity.Test.Unit/PublicApiTests/PublicClientApplicationTests.cs
@@ -10,7 +10,7 @@
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.Identity.Client;
-using Microsoft.Identity.Client.Advanced;
+using Microsoft.Identity.Client.Extensibility;
 #if NET8_0_OR_GREATER
 using Microsoft.Identity.Client.Broker;
 #endif