The Record class attribute seem to be missing from the class files of records with no record components (i.e. empty records). While according to section 4.7 of the JVM Specification the Record attribute isn't critical to the interpretation of the class file by the virtual machine they are important when inspecting the structure of the class file, by both the JDK's libraries and modding utilities. This issue impacts 9 classes in 23w31a, provided in official mappings: ClientboundStartConfigurationPacket, ServerboundConfigurationAcknowledgedPacket, ServerboundLoginAcknowledgedPacket, DiscardedQueryAnswerPayload, GuiSpriteScaling$Stretch, GameTestClearMarkersDebugPayload, ServerboundFinishConfigurationPacket, and ClientboundChunkBatchStartPacket.