$ git clone -n https://src.fedoraproject.org/rpms/perl-Test-Synopsis.git /var/lib/mock/f45-build-26863-619/root/chroot_tmpdir/scmroot/perl-Test-Synopsis
Cloning into '/var/lib/mock/f45-build-26863-619/root/chroot_tmpdir/scmroot/perl-Test-Synopsis'...
$ git fetch origin 86a1c3c403fad1cb1558ba91d734e0379edef005:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-Test-Synopsis
 * [new ref]         86a1c3c403fad1cb1558ba91d734e0379edef005 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 86a1c3c Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild