Variable data fields:
The variable data fields have tags with the pattern 0XX to 8XX. They may vary in length and may contain any text or other data needed to describe an individual authority item or other type of record. In addition to being identified by a field tag in the Directory, these fields always contain two kinds of content designation: two indicator positions stored at the beginning of each field, and a two-character subfield code preceding each data element within the field.
For more information, see: