This directory, dists, is the canonical way to access the distributions.
Each distribution can be accessed by name or state from here.

stable, or etch     - the released Debian 4.0r6.
proposed-updates    - possible updates to Debian 4.0.  See the README there.
testing, or lenny   - the development version of the next release.
unstable, or sid    - untested candidate packages for future releases.