So far, Firefly saves the table data in IPAC table format, adding extra meta data about the table as key=value in the file header before data.  When DM-15826 is implemented, Firefly will have more meta data about table supplied by VOTable, and keeping them in the saved file would be desirable. 

Develop the infrastructure and and implement csv and tsv.

Related tickets proposes to give user options to save the table in VOTable form and maybe FITS table format too.