Comment # 6 on bug 1127591 from Michael Andres

https://github.com/openSUSE/libzypp/pull/446 
for libzypp-1.14.60.

Because d.o.o insists on having metalink files per .rpm package, listing them
many create quite a lot of output. That's why I introduced a dedicated
environment variable, to list all the package mirrors we parse in the log:

  ZYPP_METALINK_DEBUG=1

(grep for lines written by `metalinkparser.cc`)