Relation between PCL2 and other tables

[sapx008]

Hello

can somebody tell me if there are relations between PCLn (e.g. PCL2) and other tables?
Table PCL2 contains the following columns

CLIENT, RELID, SRTFD, SRTF2, HISTO, AEDTM, UNAME, PGMID, VERSN, CLUSTR, CLUSTD

Is there a way to 'decrypt' the CLUSTD column?
Are there foreign keys which link PCL2 to other tables?
Does CLUSTD just link to other tables or are (e.g. payroll) data stored (encrypted) in CLUSTD?

Thanks

[thx4allthefish]

I am shadowing this in SAP Other/Abap.

Abappers are so good when it comes to relationships ...