The maven-archiver currently adds the string "Created-By: Apache Maven" to the manifest of all projects. This is good, but it needs to be more specific - e.g. Apache Maven 2.0.4. This would have two major benefits:
1) It would bring it in line with the "Build-Jdk" field, which has values like "1.5.0_09"
2) It would help in having truly repeatable builds - potentially, you need to know which version of Maven was used to build an artifact
I'd write the patch myself if I could figure out how to get at the information... it's in a @component called "runtimeInformation", but how do you access components from a low-level library like maven-archiver?