$ git clone -n https://src.fedoraproject.org/rpms/perl-System-Command.git /var/lib/mock/f45-build-26339-617/root/chroot_tmpdir/scmroot/perl-System-Command
Cloning into '/var/lib/mock/f45-build-26339-617/root/chroot_tmpdir/scmroot/perl-System-Command'...
$ git fetch origin 97aee6d7c9a93db83091ed8692680fe66f2c2ce6:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-System-Command
 * [new ref]         97aee6d7c9a93db83091ed8692680fe66f2c2ce6 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 97aee6d Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild