If you want to do this you should use ...
# This file is written by xdg-user-dirs-update
# If you want to change or add directories, just edit the line you're
# interested in. All local changes will be retained on the next run
# Format is XDG_xxx_DIR="$HOME/yyy", where yyy is a shell-escaped
# homedir-relative path, or XDG_xxx_DIR="/yyy", where /yyy is an
# absolute path. No other format is supported.
so that would be
echo $(xdg-user-dir DOWNLOAD)
and it will show the default download location (in my case
/discworld/Downloads). Works for all of these words. Like ...
echo $(xdg-user-dir DESKTOP)