What happens to Ichika after the fated summer ends?


In the final episode,

> Ichika is shown at the end of the finished movie wearing the clothes Nanami
> brought from Bolivia, so it is inferred that she somehow returned to Earth
> after being abducted by the unmanned probes from the Federation search
> party.

So my question is not about this particular part of the ending.

Is there any official material (manga, OVA, ONA, etc.) that tells **how** it
came to that ending?

> How did she return to Earth?




At the end of the last episode, Kaito's sister returns and brings a Bolivian
sweater for Ichika, but Kaito tells her she had to return to her own country
as her transfer had ended. We then see Remon at MIB headquarters with the
plans for the interstellar ship and Rinon is there with her.

If you watch till the end of the credits, one year later, some students are
watching the old class members' student film and it shows Ichika wearing the
Bolivian sweater with some revealing dialog.

