version=4
opts="filenamemangle=s/.+\/v?(\d\S+)\.tar\.gz/fred-server-$1\.tar\.gz/, uversionmangle=s/-rc/~rc/" \
  https://github.com/CZ-NIC/fred-server/tags .*/(\d\.\d{1,2}.\d{1,2}(?:-rc\d{1,2})?)\.tar\.gz
