The MANIFEST.MF files in the source bundles of Hibernate ORM are copies of the compiled bundle MANIFEST.MF files. They contain all the Export / Import-Package information and even the Bundle-SymbolicName is identical.

In our case we add the source bundles of external libraries to our target platform and because the files contain Export-Package information they get resolved in a tycho build as provider for a specific package. When this happens the build fails because the classes in the package cannot be resolved.

Despite the problems in our specific case I think source bundle MANIFEST.MF should not contain implementation information.
Often the source bundle Bundle-SymbolicName is extended with '.source' and an Eclipse-SourceBundle entry is added and all implementation details like package import/export are removed.