Contents of libtdeedu as of Jul 2005, 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.

tdeeducore:
Contains classes KEduVocData and KEduVocDataItem, for storing and parsing
vocabulary data in a QDom object.
Currently used by:  khangman, klatin

tdeeduplot:
Constains classes KPlotObject and KPlotWidget for easy plotting of 
data points, including automatic generation of labeled axes with 
"smart" tickmarks.
Currently used by:  kalzium, kstars, ktouch

tdeeduui:
Contains:
- KEduSimpleEntryDlg, a simple dialog for entering vocabulary data
- Glossary, GlossaryItem and GLossaryDialog, which can be useful to embed a
  small glossary in an application
Currently used by:  kalzium, kstars

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