The latest AS trunk build is generating the JBOSS_HOME/client/jbossall-client.jar MANIFEST.MF with unsubstituted property values:

...
Specification-Title: ${specification.title}
Specification-Version: ${specification.version}
Specification-Vendor: ${specification.vendor}
Implementation-Title: ${implementation.title}
Implementation-Version: ${implementation.version}
Implementation-Vendor: ${implementation.vendor}
Implementation-Vendor-Id: ${implementation.vendor.id}
...//rest of it

Looking at the build/build.xml i don't see where the values for these properties are being set (i haven't looked into much details, though).

On a related note, the Classpath entries in that MANIFEST.MF - is it expected to contain entries of all jars that's present in JBOSS_HOME/client folder? Or what's the criteria of adding a Classpath entry in MANIFEST.MF? I see that many jars present in JBOSS_HOME/client are missing from that list.