Unexpected files in JBossJTS jars

I noticed that there is an unexpected empty file named built_using_java_1.6 in the root of these jars in EAP 5.2.0 distribution:

./jboss-as/client/jbossjts-integration.jar
./jboss-as/client/jbossjts-jacorb.jar
./jboss-as/client/jbossjts.jar
./jboss-as/common/lib/jbossjts-integration.jar
./jboss-as/common/lib/jbossjts-jacorb.jar
./jboss-as/common/lib/jbossjts.jar
./jboss-as/common/lib/jbossts-common.jar

And an empty file named built_using_java_1.5 in file:
./seam/lib/test/jboss-embedded-all.jar

Does it have any particular meaning? If not, I think it should be removed.