$ git clone -n https://src.fedoraproject.org/rpms/expat.git /var/lib/mock/f41-build-851515-165989/root/chroot_tmpdir/scmroot/expat
Cloning into '/var/lib/mock/f41-build-851515-165989/root/chroot_tmpdir/scmroot/expat'...
$ git fetch origin 35b9b4e8281b0395f38a912e02f2a144e33234f8:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/expat
 * [new ref]         35b9b4e8281b0395f38a912e02f2a144e33234f8 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 35b9b4e Rebase to version 2.6.3