$ git clone -n https://src.fedoraproject.org/rpms/electrum.git /var/lib/mock/f42-build-side-1-3499073-45964/root/chroot_tmpdir/scmroot/electrum
Cloning into '/var/lib/mock/f42-build-side-1-3499073-45964/root/chroot_tmpdir/scmroot/electrum'...
$ git fetch origin fa187ee836434e7f0de7e60ee72d7c3060808d01:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/electrum
 * [new ref]         fa187ee836434e7f0de7e60ee72d7c3060808d01 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at fa187ee Fix finding libsecp256k1 on f42