$ git clone -n https://src.fedoraproject.org/rpms/libpqxx.git /var/lib/mock/f45-build-16801-491/root/chroot_tmpdir/scmroot/libpqxx
Cloning into '/var/lib/mock/f45-build-16801-491/root/chroot_tmpdir/scmroot/libpqxx'...
$ git fetch origin d52ad127dabb5e386a7194f2c29761b1838d1c75:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libpqxx
 * [new ref]         d52ad127dabb5e386a7194f2c29761b1838d1c75 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d52ad12 Remove stale 'xmlto' BuildRequires