diff --git a/build-data/reobf-mappings-patch.tiny b/build-data/reobf-mappings-patch.tiny
index f12c799ff7..22eb47fd86 100644
--- a/build-data/reobf-mappings-patch.tiny
+++ b/build-data/reobf-mappings-patch.tiny
@@ -11,5 +11,7 @@
 # use - at least in some capacity - for a long time.
 
 tiny	2	0	mojang+yarn	spigot
+
+# CraftBukkit changes this field's type, which causes the original mapping to miss
 c	net/minecraft/server/level/ServerLevel	net/minecraft/server/level/WorldServer
 	f	Lnet/minecraft/world/level/storage/PrimaryLevelData;	serverLevelData	E