/usr/lib/jvm/java-6-openjdk-amd64/jre/lib/amd64/jvm.cfg-default is in openjdk-6-jre-headless 6b38-1.13.10-1~deb7u1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 | # jvm.cfg-default - default jvm configuration which is used if no jvm.cfg
# is found. After unpacking the file jvm.cfg doesn't exist yet (config file),
# in this case use this file instead, so that the VM can be used before
# configuration of the runtime package.
-server KNOWN
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