$ git clone -n https://src.fedoraproject.org/rpms/perl-PDF-Builder.git /var/lib/mock/f45-build-25499-611/root/chroot_tmpdir/scmroot/perl-PDF-Builder
Cloning into '/var/lib/mock/f45-build-25499-611/root/chroot_tmpdir/scmroot/perl-PDF-Builder'...
$ git fetch origin 85bc889c0de1f096c5fc242a63ab9704bf155ef0:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-PDF-Builder
 * [new ref]         85bc889c0de1f096c5fc242a63ab9704bf155ef0 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 85bc889 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild