CMIS uses special JCR namespaces cmis and xcmis internally.
To expose drives content following nodetypes supported:
nt:file nodetype for representation of cmis:documents
nt:folder for representation of cmis:folder
Since the CMIS specification does not allow having more root types except ones described above (cmis:documents and cmis:folder), those two (nt:file and nt:folder) are mapped to CMIS types.
There are two more nodetypes which are used: cmis:policy and cmis:relationship which represent CMIS types with corresponded (see Services description for details).
Additionally, nodetypes used in WCM are mapped as follow:
nt:unstructured + extensions as cmis:folder
exo:taxonomy + extensions as cmis:folder
In other words only nodetypes extending nt:file, nt:folder, nt:unstructured and exo:taxonomy will be exposed correctly via CMIS API.
WCM's nodetype exo:article is not supported by eXo CMIS due to uncompliant structure to nt:file.