$ git clone -n https://src.fedoraproject.org/rpms/perl-BackPAN-Index.git /var/lib/mock/f45-build-21852-588/root/chroot_tmpdir/scmroot/perl-BackPAN-Index
Cloning into '/var/lib/mock/f45-build-21852-588/root/chroot_tmpdir/scmroot/perl-BackPAN-Index'...
$ git fetch origin c84bdebcaff7fdf7aee61cd67b9e2f29b85d4967:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-BackPAN-Index
 * [new ref]         c84bdebcaff7fdf7aee61cd67b9e2f29b85d4967 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c84bdeb Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild