$ git clone -n https://src.fedoraproject.org/rpms/rust-aes-siv.git /var/lib/mock/f38-build-side-42-init-devel-1082903-29855/root/chroot_tmpdir/scmroot/rust-aes-siv
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-1082903-29855/root/chroot_tmpdir/scmroot/rust-aes-siv'...
$ git fetch origin 4b8b8b0f704f44e78093ffc77b2f9b8b2d17f0d8:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-aes-siv
 * [new ref]         4b8b8b0f704f44e78093ffc77b2f9b8b2d17f0d8 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4b8b8b0 Initial import (#2214386)