Updated the summary and the Dto name.

Emby.Server.Implementations/Library/UserDataManager.cs

@@ -6,7 +6,6 @@ using System;
 using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Globalization;
-using System.Reflection;
 using System.Threading;
 using Jellyfin.Data.Entities;
 using MediaBrowser.Controller.Configuration;
@@ -82,7 +81,7 @@ namespace Emby.Server.Implementations.Library
             });
         }
 
-        public void SaveUserData(User user, BaseItem item, UserDataDto userDataDto, UserDataSaveReason reason)
+        public void SaveUserData(User user, BaseItem item, UpdateUserItemDataDto userDataDto, UserDataSaveReason reason)
         {
             ArgumentNullException.ThrowIfNull(user);
             ArgumentNullException.ThrowIfNull(item);

Jellyfin.Api/Controllers/ItemsController.cs

@@ -1,7 +1,6 @@
 using System;
 using System.ComponentModel.DataAnnotations;
 using System.Linq;
-using System.Threading;
 using Jellyfin.Api.Extensions;
 using Jellyfin.Api.Helpers;
 using Jellyfin.Api.ModelBinders;
@@ -928,7 +927,7 @@ public class ItemsController : BaseJellyfinApiController
     public ActionResult<UserItemDataDto> UpdateItemUserData(
         [FromRoute, Required] Guid userId,
         [FromRoute, Required] Guid itemId,
-        [FromBody, Required] UserDataDto userDataDto)
+        [FromBody, Required] UpdateUserItemDataDto userDataDto)
     {
         if (!RequestHelpers.AssertCanUpdateUser(_userManager, User, userId, true))
         {

MediaBrowser.Controller/Library/IUserDataManager.cs

@@ -42,7 +42,7 @@ namespace MediaBrowser.Controller.Library
         /// <param name="item">The item.</param>
         /// <param name="userDataDto">The reason for updating the user data.</param>
         /// <param name="reason">The reason.</param>
-        void SaveUserData(User user, BaseItem item, UserDataDto userDataDto, UserDataSaveReason reason);
+        void SaveUserData(User user, BaseItem item, UpdateUserItemDataDto userDataDto, UserDataSaveReason reason);
 
         UserItemData GetUserData(User user, BaseItem item);
 

MediaBrowser.Model/Dto/UserDataDto.cs → MediaBrowser.Model/Dto/UpdateUserItemDataDto.cs

@@ -1,11 +1,9 @@
 namespace MediaBrowser.Model.Dto
 {
     /// <summary>
-    /// Class UserDataDto extends UserItemDataDto to allow nullable members.
-    /// This change allow us to implement the new /Users/{UserId}/Items/{ItemId}/UserData endpoint.
-    /// This object allows the requestor to update all or specific user data fields without altering the non-nullable members state.
+    /// This is used by the api to get information about a item user data.
     /// </summary>
-    public class UserDataDto : UserItemDataDto
+    public class UpdateUserItemDataDto : UserItemDataDto
     {
         /// <summary>
         /// Gets or sets the playback position ticks.