I have no idea what a "bar-code icon" is. Do you.?

Then MergeBarCode and DisplayBarCode fields are not listed in the Insert> Field dialog. The MergeBarCode field is not in the merge fields list on the mailings tab.

The pages I listed are the only documentation of these fields of which I am aware.

No command that I've found appears in the Customize the Ribbon lists or the QAT lists of available commands.

When such a field is inserted (using Ctrl+F9) it works fine but no special context ribbon or commands show up.