Conventions for additional content of the manifest.mf file?

Question

Are there any conventions for the MANIFEST.MF file in a Java JAR beyond the JAR specification? Interesting information I might want to include are: Build date and other build information, SVN Revision, perhaps a description. I haven't found suggestions how to name the corresponding keys. Are there any de facto standards or at least common key names that are used in manifests for things that are not covered by the spec?

Answer 1

The JAR Manifest: Overview mentions that "Attributes which are not understood are ignored." Anything but a Main Attribute should be OK. Here's a somewhat more comprehensive summary link and a handy utility to examine the manifest in situ.

Answer 2

You can include any key/value pair that does not break the spec. (e.g. in length of value). As to how to do it, it would depend on what tool you are using to create the manifest.