$ git clone -n https://src.fedoraproject.org/rpms/rust-buf-min.git /var/lib/mock/f45-build-40552-773/root/chroot_tmpdir/scmroot/rust-buf-min
Cloning into '/var/lib/mock/f45-build-40552-773/root/chroot_tmpdir/scmroot/rust-buf-min'...
$ git fetch origin e489f06eab69d3b66712f6bd7a3ae3878a9b28c6:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-buf-min
 * [new ref]         e489f06eab69d3b66712f6bd7a3ae3878a9b28c6 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e489f06 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild