$ git clone -n https://src.fedoraproject.org/rpms/rust-mutate_once.git /var/lib/mock/f45-build-43293-801/root/chroot_tmpdir/scmroot/rust-mutate_once
Cloning into '/var/lib/mock/f45-build-43293-801/root/chroot_tmpdir/scmroot/rust-mutate_once'...
$ git fetch origin 6191bf7d9dd61e3233e1af2e5de61123f2fd591c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-mutate_once
 * [new ref]         6191bf7d9dd61e3233e1af2e5de61123f2fd591c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6191bf7 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild