$ git clone -n https://src.fedoraproject.org/rpms/rust-ref-cast.git /var/lib/mock/f38-build-side-42-init-devel-1396630-31051/root/chroot_tmpdir/scmroot/rust-ref-cast
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-1396630-31051/root/chroot_tmpdir/scmroot/rust-ref-cast'...
$ git fetch origin 65076eca78bce98a6f1fc43c1912f0b9af192427:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-ref-cast
 * [new ref]         65076eca78bce98a6f1fc43c1912f0b9af192427 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 65076ec Update to version 1.0.20; Fixes RHBZ#2232467