An output format.
Can be on of the following: full - plain text,
bed - BED (Browser Extensible Data) format,
see e.g. <https://genome.ucsc.edu/FAQ/FAQformat.html#format5.1>,
gff - GFF (General Feature Format),
see e.g. <https://genome.ucsc.edu/FAQ/FAQformat.html#format3>
Only full is currently supported.