How to extend an user definded table in SAP B1 10.0?

I am trying to change a selection table within our packing list menu in our SAP system, but I do not know how to do this. My colleague, who is out indefinitely, has created a table of packing materials for our warehouse staff. This table is now to be extended by two further entries. The selection table is in the packing list table DLN7. I have also shown this in the picture attached.

So far I have checked all custom tables and custom windows. However, the table displayed is not there. Does anyone know where in SAP I have to look?

I would be very happy to receive further hints on this. Thank you very much in advance.

I think this is most likely a Custom User Defined Field with set Valid Values,

Try looking through This Screen: Tools > Customization Tools > User-Defined Fields - Management

i Can't point you to the Right Section but it will be in there somewhere.

Also try a

select * from DLN7

and see what columns it returns as a way to confirm it is a UDF.