I notice I only see the Nuxeo 5.5 CAP information when i look at http://explorer.nuxeo.org/nuxeo/site/distribution/current/ v5.5 live.
It seems some items (DM?) are missing from the live v5.5 listings.
Specfically any of the mail oriented bundles:
Yes you are right.
Explorer expose only today the "Nuxeo Platform" distribution as you can see into the Version Column information. This is in fact the dedicated light distribution containing only needed bundles to make work explorer. In fact this is the description of the host.
We will soon publish into explorer DM, CMF and DAM configuration.