docs: plainer wording for the comments this PR adds

Author: NoelStephensUnity

com.unity.netcode.gameobjects/Runtime/Components/Helpers/UnifiedBootstrap.cs

@@ -107,11 +107,12 @@ public override bool Initialize(string defaultWorldName)
         }
 
         /// <summary>
-        /// Creates the world a <see cref="NetworkManager"/> runs its hybrid session in.
+        /// Creates the world used by a <see cref="NetworkManager"/>'s hybrid session.
         /// </summary>
         /// <remarks>
-        /// A server, host or not, runs in a single world host, except in a dedicated server build, where Netcode for
-        /// Entities cannot create a world that is also a client. A build for only one side cannot run a host.
+        /// A server or host uses a single world host. A dedicated server build uses a server-only world instead, because
+        /// Netcode for Entities cannot create a client world there. A build that only targets the client or the server
+        /// cannot start a host.
         /// </remarks>
         private static World CreateWorld(NetworkManager networkManager)
         {

com.unity.netcode.gameobjects/Runtime/Components/Helpers/UnifiedUpdateConnections.cs

@@ -26,14 +26,14 @@ public void SendMessage<T>(T message) where T : unmanaged, IRpcCommand
     }
 
     /// <summary>
-    /// The <see cref="NetworkManager"/> a hybrid session's world was created for, as a singleton in that world.
+    /// This is used to track the <see cref="NetworkManager"/>, as a singleton, when running a hybrid session.
     /// </summary>
     internal struct HybridNetworkManager : IComponentData
     {
         public UnityObjectRef<NetworkManager> NetworkManager;
     }
 
-    // Created only in client and server worlds, and updated only in one a NetworkManager created for a hybrid session.
+    // Only exists in client and server worlds, and only updates in a world created for a hybrid session.
     [WorldSystemFilter(WorldSystemFilterFlags.ServerSimulation | WorldSystemFilterFlags.ClientSimulation)]
     internal partial class UnifiedUpdateConnections : SystemBase
     {
@@ -53,7 +53,7 @@ protected override void OnUpdate()
         {
             var commandBuffer = new EntityCommandBuffer(Allocator.Temp);
             var networkManager = m_HybridNetworkManagerQuery.GetSingleton<HybridNetworkManager>().NetworkManager.Value;
-            // The world outlives its NetworkManager if ShutdownInternal throws before disposing it.
+            // A missing NetworkManager counts as shutting down: the world outlives it if ShutdownInternal throws before disposing the world.
             var isShuttingDown = !networkManager || networkManager.ShutdownInProgress || !networkManager.IsListening;
             foreach (var (networkId, connectionState, entity) in SystemAPI.Query<NetworkId, ConnectionState>().WithNone<NetworkStreamConnection>().WithEntityAccess())
             {
@@ -118,7 +118,7 @@ protected override void OnUpdate()
             // make sure we have disconnected all known connections.
             if (isShuttingDown)
             {
-                // Only connections that went in-game have ConnectionState, which is removed here, so each is reported once.
+                // Only in-game connections have ConnectionState, and removing it here means each one is only reported once.
                 foreach (var (networkId, entity) in SystemAPI.Query<NetworkId>().WithAll<ConnectionState>().WithEntityAccess())
                 {
                     commandBuffer.RemoveComponent<ConnectionState>(entity);

com.unity.netcode.gameobjects/Runtime/Timing/NetworkTimeSystem.cs

@@ -263,7 +263,7 @@ public bool Advance(double deltaTimeSec)
             // Move each offset toward its target by at most AdjustmentRatio of this frame's delta, stopping once it gets there.
             // Stepping the full amount every frame overshot the target, so a synced clock alternated between running fast and
             // slow, and anything driven by it juddered.
-            // A negative step would make Math.Clamp throw, so a negative delta or AdjustmentRatio adjusts nothing.
+            // Math.Clamp throws on a negative step, so a negative delta or AdjustmentRatio applies no adjustment.
             var maximumStep = Math.Max(0.0, deltaTimeSec * AdjustmentRatio);
             m_CurrentLocalTimeOffset += Math.Clamp(m_DesiredLocalTimeOffset - m_CurrentLocalTimeOffset, -maximumStep, maximumStep);
             m_CurrentServerTimeOffset += Math.Clamp(m_DesiredServerTimeOffset - m_CurrentServerTimeOffset, -maximumStep, maximumStep);

com.unity.netcode.gameobjects/Runtime/Transports/Unified/UnifiedNetcodeTransport.cs

@@ -476,7 +476,7 @@ public override void DisconnectLocalClient()
         public override ulong GetCurrentRtt(ulong clientId)
         {
             var (transportId, _) = m_NetworkManager.ConnectionManager.ClientIdToTransportId(clientId);
-            // A message handled after the connection was removed (for example while shutting down) has no RTT, as with UnityTransport.
+            // Returns 0 when the connection was already removed (for example while shutting down), the same as UnityTransport.
             return m_Connections.TryGetValue((int)transportId, out ConnectionInfo connectionInfo) ? (ulong)connectionInfo.Connection.RTT : 0;
         }
 

com.unity.netcode.gameobjects/Tests/Runtime/NetworkTransform/UnifiedNetworkTransformTest.cs

@@ -102,8 +102,7 @@ public IEnumerator BasicMovementTest()
         }
 
         /// <summary>
-        /// Validates that each <see cref="NetworkManager"/>'s world updates the connections of that
-        /// <see cref="NetworkManager"/> alone.
+        /// Validates that each <see cref="NetworkManager"/>'s world only updates that <see cref="NetworkManager"/>'s connections.
         /// </summary>
         [Test]
         public void EachWorldUpdatesConnectionsForItsOwnNetworkManager()

com.unity.netcode.gameobjects/Tests/Runtime/Unified/UnifiedUpdateConnectionsTests.cs

@@ -21,8 +21,7 @@ public void OneTimeSetup()
         }
 
         /// <summary>
-        /// Validates that a session without ghost prefabs leaves no world with a <see cref="UnifiedUpdateConnections"/>
-        /// system.
+        /// Validates that no world has a <see cref="UnifiedUpdateConnections"/> system when the session has no ghost prefabs.
         /// </summary>
         [UnityTest]
         public IEnumerator NoWorldUpdatesConnectionsWithoutGhostPrefabs()