This tool is intented to be used with the Survex cave mapping software (https://survex.com).
svxdem.py (SURVEX-DEM) creates svx files from raster DEMs exported from GRASS-GIS as ASCII files
like this:
r.out.ascii input=topo output=somefile.ascii
svxdem.py -i somefile.ascii -o somefile.svx -p UTM22S