Other partitioned, sequential or VSAM data set, or z/OS UNIX file names

You can use this field to specify any partitioned or sequential data set, or z/OS® UNIX file path name:
Other Partitioned, Sequential or VSAM Data Set, or z/OS UNIX file:
   Name . . . . .                                                            +
Note: The + at the end of the field indicates a scrollable field. The + indicates that the field may contain more data than is able to be displayed on the current screen. It is commonly used to enter long UNIX file path names but may appear on panels other than those associated with data set names.

See the descriptions of the ZEXPAND (EXPAND) and ZCLRSFLD (ZCLRSFLD) commands which operate on scrollable fields.