$ git clone -n https://src.fedoraproject.org/rpms/rust-minus.git /var/lib/mock/f39-build-2316360-58019/root/chroot_tmpdir/scmroot/rust-minus
Cloning into '/var/lib/mock/f39-build-2316360-58019/root/chroot_tmpdir/scmroot/rust-minus'...
$ git fetch origin ce7946ea998a405b2163114265de71ca5e64ebd0:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-minus
 * [new ref]         ce7946ea998a405b2163114265de71ca5e64ebd0 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at ce7946e Update to version 5.5.3; Fixes RHBZ#2252978