Currently we have a number of small metadata files:
RELEASE.version.txt(detemines the latest release of the artifact)
SNAPSHOT.version.txt(determines the timestamp/build# of the latest build of the artifact)
LATEST.version.txt(determines the latest build of the artifact, whether it be a timestamp or a release)
plugins.xml(maps plugin prefixes to artifact Id within the group)
With the advent of version ranges, this will require use to get a list of versions for an artifact also. This has gotten to "critical mass" of metadata that we should move to handling general directory metadata.