You're not missing anything. There's a bug in the build.xml that I
used to generate it. I'm working on it.
We do run test-built-jars as part of our pre-release process:
http://code.google.com/p/closure-templates/source/browse/trunk/build.xml#521
It tests the jars that *should* be included in the zips. It does not
zip everything up, then extract the jars so it did not catch this
problem.
Internally, we do not use ant to build much, so the problem in
build.xml went unnoticed.