Would you give a command-line example using the new optional third argument to PDF.attachFile?

PDF.attachFile is a JavaScript method, so you would need to call it from a script that is referenced from the document (and enabled with the --javascript option) or by specifying the script on the command-line with the --script option.

Right I meant to say the --attach option. i.e:
... --attach="82 FR 30772 (id-20170703-reid-19).pdf" to filename 82 FR 30722(19)

The attach option doesn't support the filename or description arguments, the embedded filename will match the name of whatever file is attached.

The job control interface does support these, though.