The Download Manager for Mathematica 11.3 does manage all kinds of useful things like display language and download speed, but seems to lack an option for setting the download folder. How can I specify the target folder used by the Download Manager on Windows?

As it is now, the manager will download all installation files into $HomeDirectory/Downloads, but I am limited by how the computer is set up and only have a tiny C:\ partition that can't accomodate 4 GB of temporary data. I would like to download to the D:\ partition instead (which has plenty of space). Is there a workaround?