The DISPLAY.LIKE keyword is a field qualifier which causes the field to be displayed using the attributes of another field defined in the dictionary.
field.name DISPLAY.LIKE other.field
The DISPLAY.LIKE keyword causes the attributes of other.field to be used when displaying field.name. The attributes are the display name, conversion, format, single / multiple value flag and association. The COL.HDG, CONV, FMT, SINGLE.VALUE, MULTI.VALUE, ASSOC and ASSOC.WITH field qualifiers can be used to further modify the attributes.
LIST INVOICES EVAL "ISSUE.DATE + 90" DISPLAY.LIKE DUE.DATE COL.HDG "Reminder date"
This command processes records from the INVOICES file and reports the record id (probably the invoice number) and the date 90 days after that stored in the ISSUE.DATE field using the attributes of the DUE.DATE field except for the column heading which is specifically set.