$ git clone -n https://src.fedoraproject.org/rpms/rust-bincode.git /var/lib/mock/f45-build-40450-772/root/chroot_tmpdir/scmroot/rust-bincode
Cloning into '/var/lib/mock/f45-build-40450-772/root/chroot_tmpdir/scmroot/rust-bincode'...
$ git fetch origin def4f9418ecbef6b745f55bceb5e6a7f6654afcd:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-bincode
 * [new ref]         def4f9418ecbef6b745f55bceb5e6a7f6654afcd -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at def4f94 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild