Issues with Repository:
Some aspects are best servered with metadata, but metadata sources don't agree on naming.
Naming issues exist:
Groups. How are groups determined for a known id?
ID 'jdt' is in Group 'eclipse'.
How does a user (tool) go from package to group/id?
org.apache.eclipse.jdt is group 'eclipse', id 'jdt' but with no gauranteed algorythm.