$ git clone -n https://src.fedoraproject.org/rpms/erlang-hex_core.git /var/lib/mock/f40-build-1898203-25068/root/chroot_tmpdir/scmroot/erlang-hex_core
Cloning into '/var/lib/mock/f40-build-1898203-25068/root/chroot_tmpdir/scmroot/erlang-hex_core'...
$ git fetch origin 41222001285d23ca52ce6c2698ed817743f3b914:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/erlang-hex_core
 * [new ref]         41222001285d23ca52ce6c2698ed817743f3b914 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4122200 hex_core ver. 0.10.3