man ssconvert has multiple issues
First issue: 'man ssconvert' shows: -v, --version Display ssconvert's version.
Contrary to this, ssconvert -v shows:
$ ssconvert -v
Usage: ssconvert [OPTION...] INFILE [OUTFILE]
snoopy:$ ssconvert --version
ssconvert version '1.12.43'
datadir := '/usr/share/gnumeric/1.12.43'
libdir := '/usr/lib/gnumeric/1.12.43'
A second issue: For the txt exporter, the man page specifies: OPTIONS FOR THE CONFIGURABLE TEXT (*.txt) EXPORTER sheet Name of the workbook sheet to operate on. You can specify several sheets by repeat‐ ing this option. If this option is not given the active sheet (i. e. the sheet that was active when the file was saved) is used.
However, I notice that all the sheets are converted, not only the active one.
Third "issue": By the way, man page specifies that last update of the man page is 2011.