CLASS qw net/minecraft/migration/MigrationHandlerBuilder
METHOD a build ()Lqv;
METHOD a upgradeStack (Lqu;Lfc;ILjava/lang/String;)Lfc;
METHOD a registerTagUpgraders (Lqv;)V
METHOD b upgradeStackList (Lqu;Lfc;ILjava/lang/String;)Lfc;