$ git clone -n https://src.fedoraproject.org/rpms/rust-chrono.git /var/lib/mock/f40-build-2727279-73126/root/chroot_tmpdir/scmroot/rust-chrono
Cloning into '/var/lib/mock/f40-build-2727279-73126/root/chroot_tmpdir/scmroot/rust-chrono'...
$ git fetch origin c4bb4770c9757e72794e83da0936049431d8eeb2:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-chrono
 * [new ref]         c4bb4770c9757e72794e83da0936049431d8eeb2 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c4bb477 Update to version 0.4.38; Fixes RHBZ#2271640