Here are some places where you can look for information about ABC (Atlas Based Classification):

Forums
  1. open-discussion: General Discussion
  2. help: Get Public Help
Trackers
  1. Bugs: Bug Tracking System
  2. Support: Tech Support Tracking System
  3. Patches: Patch Tracking System
  4. Feature Requests: Feature Request Tracking System
Wiki
ABC (Atlas Based Classification) has a wiki that can be found here.