$ git clone -n https://src.fedoraproject.org/rpms/perl-Class-Singleton.git /var/lib/mock/f45-build-22419-591/root/chroot_tmpdir/scmroot/perl-Class-Singleton
Cloning into '/var/lib/mock/f45-build-22419-591/root/chroot_tmpdir/scmroot/perl-Class-Singleton'...
$ git fetch origin c80693e328765ca4a0a350ff05e5b875d7a0bf88:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-Class-Singleton
 * [new ref]         c80693e328765ca4a0a350ff05e5b875d7a0bf88 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c80693e Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild