$ git clone -n https://src.fedoraproject.org/rpms/rust-twox-hash.git /var/lib/mock/f42-build-side-1-3586987-46927/root/chroot_tmpdir/scmroot/rust-twox-hash
Cloning into '/var/lib/mock/f42-build-side-1-3586987-46927/root/chroot_tmpdir/scmroot/rust-twox-hash'...
$ git fetch origin ebb9902435dd10f92e34f1fafcd1c444372f98c9:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-twox-hash
 * [new ref]         ebb9902435dd10f92e34f1fafcd1c444372f98c9 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at ebb9902 Update to version 2.1.1; Fixes RHBZ#2371180