The files can be opened with as Spreadsheet Reader (e. g. Excel).
The sheet USt2A - Felder includes the codes and description (columns B and C), as well as allowed values, length and regex expression every field validates against (columns E, F and I). This also applies to attachments to the main form (eg. UN - Felder).
Rows marked as(alt) denote, that a change has been made to its parameters (eg. Context) compared to the previous version of the documentation.
Forms
The forms have a 7-digit ELSTER field code number printed on it (blue).