$ git clone -n https://src.fedoraproject.org/rpms/rust-crossbeam-utils.git /var/lib/mock/f40-build-1910170-25079/root/chroot_tmpdir/scmroot/rust-crossbeam-utils
Cloning into '/var/lib/mock/f40-build-1910170-25079/root/chroot_tmpdir/scmroot/rust-crossbeam-utils'...
$ git fetch origin b1cff012832d60b9b341249cb02cc9525e3c62f7:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-crossbeam-utils
 * [new ref]         b1cff012832d60b9b341249cb02cc9525e3c62f7 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b1cff01 Update to version 0.8.20; Fixes RHBZ#2281540