What you want is in the System Administration Guide (Chapter 16). It has the use, options and defaults of both Server and workstation JDE.INI files. I have a Feb 2001 soft (PDF, 3781 kb) copy of it.
Not all sections and parameters are documented in a publically available document. Your best bet is to post a question related to a specific setting or section, or to open a case with PeopleSoft (AKA Oracle).