$ git clone -n https://src.fedoraproject.org/rpms/rust-macrotest.git /var/lib/mock/f45-build-43103-800/root/chroot_tmpdir/scmroot/rust-macrotest
Cloning into '/var/lib/mock/f45-build-43103-800/root/chroot_tmpdir/scmroot/rust-macrotest'...
$ git fetch origin 5bdf1651b0088d8e0aa5a8de0db39630a8a4e1a6:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-macrotest
 * [new ref]         5bdf1651b0088d8e0aa5a8de0db39630a8a4e1a6 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 5bdf165 Initial package; Resolves: rhbz#2498496