$ git clone -n https://src.fedoraproject.org/rpms/rust-atomic-waker.git /var/lib/mock/f39-build-1499494-34745/root/chroot_tmpdir/scmroot/rust-atomic-waker
Cloning into '/var/lib/mock/f39-build-1499494-34745/root/chroot_tmpdir/scmroot/rust-atomic-waker'...
$ git fetch origin b4ab2e93738bfa05c380b15303d27134f617d422:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-atomic-waker
 * [new ref]         b4ab2e93738bfa05c380b15303d27134f617d422 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b4ab2e9 Update to version 1.1.2; Fixes RHBZ#2240666