Parashas Behar · Aliyah 5 · Passuk 25:31
Chabad.org — English translation + Rashi
Torah Temimah cites Sifra / Arakhin 33b.
English: “And the houses of the open courtyards.” This teaches that houses of open courtyards are [treated] like the field of the land.
Classical derasha (Sifra / Bavli Arakhin).
Houses in unwalled settlements follow the rules of open fields: they may be redeemed indefinitely and revert at Yovel.