Modified MANIFEST.MF file for eclipse jars packaged from folders with eclipse:to-maven

The MANIFEST.MF file of some Eclipse jars deployed on the http://repo1.maven.org/maven2 repository using the eclipse:to-maven goal has been modified.
When using these jars within Eclipse, the jar signing verification fails.

The line "Archiver-Version : Plexus Archiver" has been added to the original MANIFEST.MF.

This issue seems to apply only on Eclipse jars that are packaged as folder in the 'plugins' folder of an Eclipse installation.

The following (at least) packages fails verification with eclipse:

• org.eclipse.core.runtime.compatibility.registry plugin, version 3.2.100-v20070316
• org.eclipse.ui.workbench.compatibility plugin, version 3.2.0.I20070319-0010

For instance in the org.eclipse.core.runtime.compatibility.registry plugin, version 3.2.100-v20070316 plugin, not only the MANIFEST.MF file is modified in the way I described earlier, but the SHA1-Digest of the runtime_registry_compatibilty.jar has been changed too (and thus the file itself).