$ git clone -n https://src.fedoraproject.org/rpms/rust-chrono.git /var/lib/mock/f40-build-2189933-51418/root/chroot_tmpdir/scmroot/rust-chrono
Cloning into '/var/lib/mock/f40-build-2189933-51418/root/chroot_tmpdir/scmroot/rust-chrono'...
$ git fetch origin 657712cdf47afaa28ec90a9e2511764f3413897c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-chrono
 * [new ref]         657712cdf47afaa28ec90a9e2511764f3413897c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 657712c Update to version 0.4.31; Fixes RHBZ#2236287