Hadith 3452

(2) The statement: “He has nothing”: The issues of this type are based on two principles: one, everything included in the customary meaning of sale is part of the sold item, even if not explicitly mentioned; two, what is permanently attached to the sold item, meant to remain, is included as subsidiary, but what is meant to be separated by human action is not permanently attached and not included as subsidiary. This is gathered from Al-Inayah and Ad-Durr Al-Mukhtar.