$ git clone -n https://src.fedoraproject.org/rpms/perl-Browser-Open.git /var/lib/mock/f45-build-21902-588/root/chroot_tmpdir/scmroot/perl-Browser-Open
Cloning into '/var/lib/mock/f45-build-21902-588/root/chroot_tmpdir/scmroot/perl-Browser-Open'...
$ git fetch origin 3878d830d141fff0d5147ffe3b81a117eded6428:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-Browser-Open
 * [new ref]         3878d830d141fff0d5147ffe3b81a117eded6428 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3878d83 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild