diff --git a/libguestfs.spec b/libguestfs.spec
index c01bba8..4418867 100644
--- a/libguestfs.spec
+++ b/libguestfs.spec
@@ -724,6 +724,8 @@ if ping -c 3 -w 20 8.8.8.8 && wget http://libguestfs.org -O /dev/null; then
   extra=
 else
   mkdir cachedir repo
+  # For an explanation of what we are doing here, see:
+  # https://lists.fedorahosted.org/archives/list/koji-devel@lists.fedorahosted.org/thread/ZIBY53JAURLT3QRBBJIJJ7EZWLZDE3TI/
   # -n 1 because of RHBZ#980502.
   find /var/cache/{dnf,yum} -type f -name '*.rpm' -print0 | \
     xargs -0 -n 1 cp -t repo