Contents of libkdeedu as of Feb 2006, and brief description of each module:

extdate:
Contains a reimplementation of QDate named ExtDate which eliminates the
limitation on the year (1752-8000) imposed by QDate.  Also contains
related reimplemented classes such as ExtDateTime, ExtDatePicker,
ExtDateTimeEdit, and ExtCalendarSystem.
Currently used by:  kstars

kdeeducore:
Contains KEduVocDocument and its related class for reading from/writing to the
KVTML format (and others too).
Currently used by:  kanagram, khangman, klatin, kvoctrain, kwordquiz

libscience:
Contains some classes related to scientific data, like chemical Element's,
spectra, temperature units and Isotope's.
Currently used by:  kalzium

ideas: stub directory, contains generic README and TODO files.