[What is meant by “selling land with its rights”?]

Answer: Parcels today—whether for houses or farms—in our setting do not entail any rights owed by the seller. The buyer is entitled only to the specified plot, unless a right (e.g., an access road) is expressly stipulated in the sale; then the stipulation governs.
Source: Min Thimār al-ʿIlm wa al-Ḥikmah vol.2