The field definitions were dropped from OWB help for one reason or other.
You can get the latest referecnce which is for OWB 1.1.6 if you download the that version from the ITdesign website. ITDesign the the CA partner developing OWB.
http://www.itdesign.de/fileadmin/user_upload/Downloads/Open_Workbench_Setup_1.1.6.exe
That contains the help version which has the field reference. The data model has been changed somewhat since then, but the basic fields are there.
You need also something to display WIndows legacy help which is not a standard component of WIndows any more eg. winhlp32.exe and the associated files.
A list of the bare field names for the field names for OWB 1.1.4 is at
http://www.nbl.fi/that_man/Dataelements/Datalements.htm
That was the last version where the source fiels were available.
Creata an idea in the ideation for publishing the field reference again.
Martti K.