org-table-export-default-format

org-table-export-default-format is a variable defined in `org-table.el'.
Its value is

"orgtbl-to-tsv"

Documentation:
Default export parameters for `org-table-export'.
These can be overridden for a specific table by setting the
TABLE_EXPORT_FORMAT property. See the manual section on orgtbl
radio tables for the different export transformations and
available parameters.

You can customize this variable.