A Feature can be construction or manufacturing feature see class info: Dtk_feat. It can be associated with any Dtk_Node type. Until now, Feature read is only available from :

CATIA V5
CATIA V6
NX / Unigraphics
SOLIDWORKS
Creo Parametric
libraries and needs a specific licence.

See Feature mapping in readers menu :
Readers Mapping
Browse Dtk_Feature