diff --git a/sources/src/main/java/co/aikar/timings/TimingHandler.java b/sources/src/main/java/co/aikar/timings/TimingHandler.java
index f51b4eeb2..72950f91d 100644
--- a/sources/src/main/java/co/aikar/timings/TimingHandler.java
+++ b/sources/src/main/java/co/aikar/timings/TimingHandler.java
@@ -30,10 +30,8 @@ import org.bukkit.Bukkit;
 import java.util.logging.Level;
 
 /**
- * <b>Akarin Changes Note</b><br>
- * <br>
- * 1) Add volatile to fields<br>
- * @author cakoyo
+ * Akarin Changes Note
+ * 1) Add volatile to fields (safety issue)
  */
 class TimingHandler implements Timing {
 
diff --git a/sources/src/main/java/io/akarin/server/mixin/lighting/MixinChunk.java b/sources/src/main/java/io/akarin/server/mixin/lighting/MixinChunk.java
index 755c41fba..b2d682a85 100644
--- a/sources/src/main/java/io/akarin/server/mixin/lighting/MixinChunk.java
+++ b/sources/src/main/java/io/akarin/server/mixin/lighting/MixinChunk.java
@@ -293,7 +293,7 @@ public abstract class MixinChunk implements IMixinChunk {
                     if (chunk == null) {
                         continue;
                     }
-                    chunk.checkLightSide(enumfacing.opposite());
+                    chunk.a(enumfacing.opposite()); // PAIL: checkLightSide
                 }
                 
                 this.setSkylightUpdated();
diff --git a/sources/src/main/java/net/minecraft/server/Chunk.java b/sources/src/main/java/net/minecraft/server/Chunk.java
index 245ac4ff3..42acb6d9a 100644
--- a/sources/src/main/java/net/minecraft/server/Chunk.java
+++ b/sources/src/main/java/net/minecraft/server/Chunk.java
@@ -20,11 +20,9 @@ import org.bukkit.Server; // CraftBukkit
 import org.bukkit.craftbukkit.util.CraftMagicNumbers; // Paper
 
 /**
- * <b>Akarin Changes Note</b><br>
- * <br>
- * 1) Add volatile to fields<br>
- * 2) Add OBFHELPER<br>
- * @author cakoyo
+ * Akarin Changes Note
+ * 1) Add volatile to fields (async lighting)
+ * 2) Expose private methods (async lighting)
  */
 public class Chunk {
 
@@ -1340,8 +1338,7 @@ public class Chunk {
         this.h(false);
     }
 
-    public void checkLightSide(EnumDirection direction) { a(direction); } // Akarin - OBFHELPER
-    private void a(EnumDirection enumdirection) {
+    public void a(EnumDirection enumdirection) { // Akarin - private -> public
         if (this.done) {
             int i;
 
diff --git a/sources/src/main/java/net/minecraft/server/EnchantmentManager.java b/sources/src/main/java/net/minecraft/server/EnchantmentManager.java
index e86e978fc..10e89e7e9 100644
--- a/sources/src/main/java/net/minecraft/server/EnchantmentManager.java
+++ b/sources/src/main/java/net/minecraft/server/EnchantmentManager.java
@@ -11,10 +11,8 @@ import java.util.Random;
 import java.util.Map.Entry;
 
 /**
- * <b>Akarin Changes Note</b><br>
- * <br>
- * 1) Expose private members<br>
- * @author cakoyo
+ * Akarin Changes Note
+ * 1) Expose private members (cause mixin errors)
  */
 public class EnchantmentManager {
 
diff --git a/sources/src/main/java/net/minecraft/server/EntityPlayer.java b/sources/src/main/java/net/minecraft/server/EntityPlayer.java
index 4c5cf0cbf..e22dbfdea 100644
--- a/sources/src/main/java/net/minecraft/server/EntityPlayer.java
+++ b/sources/src/main/java/net/minecraft/server/EntityPlayer.java
@@ -32,10 +32,9 @@ import org.bukkit.inventory.MainHand;
 // CraftBukkit end
 
 /**
- * <b>Akarin Changes Note</b><br>
- * <br>
- * 1) Add volatile to fields<br>
- * @author cakoyo
+ * Akarin Changes Note
+ * 1) Add volatile to fields (time update)
+ * 2) Add lock to player track (safety issue)
  */
 public class EntityPlayer extends EntityHuman implements ICrafting {
 
diff --git a/sources/src/main/java/net/minecraft/server/EntityTracker.java b/sources/src/main/java/net/minecraft/server/EntityTracker.java
index eb92f4155..aeb5a8cd3 100644
--- a/sources/src/main/java/net/minecraft/server/EntityTracker.java
+++ b/sources/src/main/java/net/minecraft/server/EntityTracker.java
@@ -12,10 +12,8 @@ import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
 /**
- * <b>Akarin Changes Note</b><br>
- * <br>
- * 1) Add lock for entries-set operations<br>
- * @author cakoyo
+ * Akarin Changes Note
+ * 1) Add lock for entries set operations (safety issue)
  */
 public class EntityTracker {
 
diff --git a/sources/src/main/java/net/minecraft/server/EntityTrackerEntry.java b/sources/src/main/java/net/minecraft/server/EntityTrackerEntry.java
index 66a9c2625..6645c26ea 100644
--- a/sources/src/main/java/net/minecraft/server/EntityTrackerEntry.java
+++ b/sources/src/main/java/net/minecraft/server/EntityTrackerEntry.java
@@ -13,6 +13,10 @@ import org.bukkit.entity.Player;
 import org.bukkit.event.player.PlayerVelocityEvent;
 // CraftBukkit end
 
+/**
+ * Akarin Changes Note
+ * 1) Make trackedPlayerMap thread-safe (safety issue)
+ */
 public class EntityTrackerEntry {
 
     private static final Logger c = LogManager.getLogger();
diff --git a/sources/src/main/java/net/minecraft/server/EnumDirection.java b/sources/src/main/java/net/minecraft/server/EnumDirection.java
index 53e445c9b..141e1c302 100644
--- a/sources/src/main/java/net/minecraft/server/EnumDirection.java
+++ b/sources/src/main/java/net/minecraft/server/EnumDirection.java
@@ -10,10 +10,8 @@ import java.util.Random;
 import javax.annotation.Nullable;
 
 /**
- * <b>Akarin Changes Note</b><br>
- * <br>
- * 1) Add OBFHELPER<br>
- * @author cakoyo
+ * Akarin Changes Note
+ * 1) Add OBFHELPER (panda redstone)
  */
 public enum EnumDirection implements INamable {
 
diff --git a/sources/src/main/java/net/minecraft/server/ItemEnderEye.java b/sources/src/main/java/net/minecraft/server/ItemEnderEye.java
index ae70e0e73..57bab9f03 100644
--- a/sources/src/main/java/net/minecraft/server/ItemEnderEye.java
+++ b/sources/src/main/java/net/minecraft/server/ItemEnderEye.java
@@ -3,10 +3,8 @@ package net.minecraft.server;
 import io.akarin.server.core.AkarinGlobalConfig;
 
 /**
- * <b>Akarin Changes Note</b><br>
- * <br>
- * 1) Add end portal disable feature<br>
- * @author cakoyo
+ * Akarin Changes Note
+ * 1) Add end portal disable feature (feature)
  */
 public class ItemEnderEye extends Item {
 
diff --git a/sources/src/main/java/net/minecraft/server/MinecraftServer.java b/sources/src/main/java/net/minecraft/server/MinecraftServer.java
index e9bf949cd..d2f7ecd79 100644
--- a/sources/src/main/java/net/minecraft/server/MinecraftServer.java
+++ b/sources/src/main/java/net/minecraft/server/MinecraftServer.java
@@ -43,6 +43,10 @@ import joptsimple.OptionSet;
 import org.spigotmc.SlackActivityAccountant; // Spigot
 import co.aikar.timings.MinecraftTimings; // Paper
 
+/**
+ * Akarin Changes Note
+ * 1) Make worlds list thread-safe (slack service)
+ */
 public abstract class MinecraftServer implements ICommandListener, Runnable, IAsyncTaskHandler, IMojangStatistics {
 
     private static MinecraftServer SERVER; // Paper
diff --git a/sources/src/main/java/net/minecraft/server/NetworkManager.java b/sources/src/main/java/net/minecraft/server/NetworkManager.java
index e0439887d..047c67c29 100644
--- a/sources/src/main/java/net/minecraft/server/NetworkManager.java
+++ b/sources/src/main/java/net/minecraft/server/NetworkManager.java
@@ -32,11 +32,11 @@ import org.apache.logging.log4j.Marker;
 import org.apache.logging.log4j.MarkerManager;
 
 /**
- * <b>Akarin Changes Note</b><br>
- * <br>
- * 1) Add volatile to fields<br>
- * 2) Expose private members<br>
- * @author cakoyo
+ * Akarin Changes Note
+ * 1) Add volatile to fields (nsc)
+ * 2) Expose private members (nsc)
+ * 3) Changes lock type to updatable lock (compatibility)
+ * 4) Removes unneed array creation (performance)
  */
 public class NetworkManager extends SimpleChannelInboundHandler<Packet<?>> {
 
diff --git a/sources/src/main/java/net/minecraft/server/PaperLightingQueue.java b/sources/src/main/java/net/minecraft/server/PaperLightingQueue.java
deleted file mode 100644
index 8fa62c20b..000000000
--- a/sources/src/main/java/net/minecraft/server/PaperLightingQueue.java
+++ /dev/null
@@ -1,98 +0,0 @@
-package net.minecraft.server;
-
-import co.aikar.timings.Timing;
-import it.unimi.dsi.fastutil.objects.ObjectCollection;
-
-import java.util.ArrayDeque;
-
-/**
- * <b>Akarin Changes Note</b><br>
- * <br>
- * 1) Expose private members<br>
- * @author cakoyo
- */
-class PaperLightingQueue {
-    private static final long MAX_TIME = (long) (1000000000 / 20 * .95);
-    private static int updatesThisTick;
-
-
-    static void processQueue(long curTime) {
-        updatesThisTick = 0;
-
-        final long startTime = System.nanoTime();
-        final long maxTickTime = MAX_TIME - (startTime - curTime);
-
-        START:
-        for (World world : MinecraftServer.getServer().worlds) {
-            if (!world.paperConfig.queueLightUpdates) {
-                continue;
-            }
-
-            ObjectCollection<Chunk> loadedChunks = ((WorldServer) world).getChunkProviderServer().chunks.values();
-            for (Chunk chunk : loadedChunks.toArray(new Chunk[loadedChunks.size()])) {
-                if (chunk.lightingQueue.processQueue(startTime, maxTickTime)) {
-                    break START;
-                }
-            }
-        }
-    }
-
-    public static class LightingQueue extends ArrayDeque<Runnable> { // Akarin - public
-        final private Chunk chunk;
-
-        LightingQueue(Chunk chunk) {
-            super();
-            this.chunk = chunk;
-        }
-
-        /**
-         * Processes the lighting queue for this chunk
-         *
-         * @param startTime If start Time is 0, we will not limit execution time
-         * @param maxTickTime Maximum time to spend processing lighting updates
-         * @return true to abort processing furthur lighting updates
-         */
-        private boolean processQueue(long startTime, long maxTickTime) {
-            if (this.isEmpty()) {
-                return false;
-            }
-            try (Timing ignored = chunk.world.timings.lightingQueueTimer.startTiming()) {
-                Runnable lightUpdate;
-                while ((lightUpdate = this.poll()) != null) {
-                    lightUpdate.run();
-                    if (startTime > 0 && ++PaperLightingQueue.updatesThisTick % 10 == 0 && PaperLightingQueue.updatesThisTick > 10) {
-                        if (System.nanoTime() - startTime > maxTickTime) {
-                            return true;
-                        }
-                    }
-                }
-            }
-
-            return false;
-        }
-
-        /**
-         * Flushes lighting updates to unload the chunk
-         */
-        public void processUnload() { // Akarin - public
-            if (!chunk.world.paperConfig.queueLightUpdates) {
-                return;
-            }
-            processQueue(0, 0); // No timeout
-
-            final int radius = 1; // TODO: bitflip, why should this ever be 2?
-            for (int x = chunk.locX - radius; x <= chunk.locX + radius; ++x) {
-                for (int z = chunk.locZ - radius; z <= chunk.locZ + radius; ++z) {
-                    if (x == chunk.locX && z == chunk.locZ) {
-                        continue;
-                    }
-
-                    Chunk neighbor = MCUtil.getLoadedChunkWithoutMarkingActive(chunk.world, x, z);
-                    if (neighbor != null) {
-                        neighbor.lightingQueue.processQueue(0, 0); // No timeout
-                    }
-                }
-            }
-        }
-    }
-}
diff --git a/sources/src/main/java/net/minecraft/server/PlayerChunk.java b/sources/src/main/java/net/minecraft/server/PlayerChunk.java
index bc0434a51..aa5e8722f 100644
--- a/sources/src/main/java/net/minecraft/server/PlayerChunk.java
+++ b/sources/src/main/java/net/minecraft/server/PlayerChunk.java
@@ -14,10 +14,8 @@ import org.bukkit.craftbukkit.chunkio.ChunkIOExecutor;
 // CraftBukkit end
 
 /**
- * <b>Akarin Changes Note</b><br>
- * <br>
- * 1) Check player list empty<br>
- * @author cakoyo
+ * Akarin Changes Note
+ * 1) Check whether players empty (performance, MC-120780)
  */
 public class PlayerChunk {
 
diff --git a/sources/src/main/java/net/minecraft/server/PlayerConnection.java b/sources/src/main/java/net/minecraft/server/PlayerConnection.java
index e247281db..f892a865e 100644
--- a/sources/src/main/java/net/minecraft/server/PlayerConnection.java
+++ b/sources/src/main/java/net/minecraft/server/PlayerConnection.java
@@ -62,12 +62,11 @@ import co.aikar.timings.MinecraftTimings; // Paper
 // CraftBukkit end
 
 /**
- * <b>Akarin Changes Note</b><br>
- * <br>
- * 1) Add volatile to fields<br>
- * 2) Expose private members<br>
- * 3) Migrated keep alive packet handling to service thread<br>
- * @author cakoyo
+ * Akarin Changes Note
+ * 1) Add volatile to fields (slack service)
+ * 2) Expose private members (slack service)
+ * 3) Removed keep-alive codes (slack service)
+ * 4) Accessible keep-alive limit (feature, compatibility)
  */
 public class PlayerConnection implements PacketListenerPlayIn, ITickable {
 
diff --git a/sources/src/main/java/net/minecraft/server/PlayerList.java b/sources/src/main/java/net/minecraft/server/PlayerList.java
index ce4b58d43..0ec255217 100644
--- a/sources/src/main/java/net/minecraft/server/PlayerList.java
+++ b/sources/src/main/java/net/minecraft/server/PlayerList.java
@@ -48,10 +48,8 @@ import org.spigotmc.event.player.PlayerSpawnLocationEvent;
 // CraftBukkit end
 
 /**
- * <b>Akarin Changes Note</b><br>
- * <br>
- * 1) Modify disconnect and connect messages<br>
- * @author cakoyo
+ * Akarin Changes Note
+ * 1) Changes (dis)connect messages (feature)
  */
 public abstract class PlayerList {
 
diff --git a/sources/src/main/java/net/minecraft/server/TileEntitySkull.java b/sources/src/main/java/net/minecraft/server/TileEntitySkull.java
index df58de738..60aa80fa8 100644
--- a/sources/src/main/java/net/minecraft/server/TileEntitySkull.java
+++ b/sources/src/main/java/net/minecraft/server/TileEntitySkull.java
@@ -24,6 +24,10 @@ import com.mojang.authlib.ProfileLookupCallback;
 import java.util.concurrent.Callable;
 // Spigot end
 
+/**
+ * Akarin Changes Note
+ * 1) Guava -> Caffeine (performance)
+ */
 public class TileEntitySkull extends TileEntity /*implements ITickable*/ { // Paper - remove tickable
 
     private int a;
diff --git a/sources/src/main/java/net/minecraft/server/WorldData.java b/sources/src/main/java/net/minecraft/server/WorldData.java
index 943557e68..0c64de254 100644
--- a/sources/src/main/java/net/minecraft/server/WorldData.java
+++ b/sources/src/main/java/net/minecraft/server/WorldData.java
@@ -12,10 +12,8 @@ import org.bukkit.event.weather.WeatherChangeEvent;
 // CraftBukkit end
 
 /**
- * <b>Akarin Changes Note</b><br>
- * <br>
- * 1) Add volatile to fields<br>
- * @author cakoyo
+ * Akarin Changes Note
+ * 1) Add volatile to fields (slack service)
  */
 public class WorldData {
 
diff --git a/sources/src/main/java/net/minecraft/server/WorldServer.java b/sources/src/main/java/net/minecraft/server/WorldServer.java
index 27c0c28b4..d1931dae2 100644
--- a/sources/src/main/java/net/minecraft/server/WorldServer.java
+++ b/sources/src/main/java/net/minecraft/server/WorldServer.java
@@ -27,10 +27,9 @@ import org.bukkit.event.weather.LightningStrikeEvent;
 // CraftBukkit end
 
 /**
- * <b>Akarin Changes Note</b><br>
- * <br>
- * 1) Expose private members<br>
- * @author cakoyo
+ * Akarin Changes Note
+ * 1) Expose private members (core, safety issue)
+ * 2) Removed hardcore difficulty codes (slack service, feature)
  */
 public class WorldServer extends World implements IAsyncTaskHandler {
 
diff --git a/sources/src/main/java/org/bukkit/craftbukkit/CraftServer.java b/sources/src/main/java/org/bukkit/craftbukkit/CraftServer.java
index c34dfc198..71583c422 100644
--- a/sources/src/main/java/org/bukkit/craftbukkit/CraftServer.java
+++ b/sources/src/main/java/org/bukkit/craftbukkit/CraftServer.java
@@ -138,7 +138,10 @@ import net.md_5.bungee.api.chat.BaseComponent;
 import javax.annotation.Nullable; // Paper
 import javax.annotation.Nonnull; // Paper
 
-
+/**
+ * Akarin Changes Note
+ * 1) Guava -> Caffeine (performance)
+ */
 public final class CraftServer implements Server {
     private final String serverName = "Paper";
     private final String serverVersion;
diff --git a/sources/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java b/sources/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
index 6b7455acc..66c757e17 100644
--- a/sources/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
+++ b/sources/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
@@ -76,10 +76,8 @@ import org.bukkit.scoreboard.Scoreboard;
 import javax.annotation.Nullable;
 
 /**
- * <b>Akarin Changes Note</b><br>
- * <br>
- * 1) Make hidden-players-set concurrent<br>
- * @author cakoyo
+ * Akarin Changes Note
+ * 1) Make hidden players thread-safe (safety issue)
  */
 @DelegateDeserialization(CraftOfflinePlayer.class)
 public class CraftPlayer extends CraftHumanEntity implements Player {