Passing both name and version arguments is probably a mistake.
stdenv.mkDerivation can create the derivation name automatically by joining its pname and version arguments as ${pname}-${version}. This does not happen if you pass name argument explicitly – in that case, you will be responsible for appending version string to the derivation name.
In most cases you can just pass separate project name (pname) and version arguments and forget about the derivation name.
mkDerivation only started supporting that relatively recently so you may find older expressions that explicitly construct name.
When you want to distinguish multiple variants of a project in the derivation name but want to keep the pname argument the same.