‘Amir Al Sha’bi said “The Prophet ﷺ had a special portion in the booty called safi. This would be a slave if he desired or a slave girl if he desired or a horse if he desired. He would choose it before taking out the fifth.” (Using translation from Abū Dāʾūd 2991)
كَانَ لِلنَّبِيِّ ﷺ سَهْمٌ يُدْعَى سَهْمَ الصَّفِيِّ إِنْ شَاءَ عَبْدًا وَإِنْ شَاءَ أَمَةً وَإِنْ شَاءَ فَرَسًا يَخْتَارُهُ قَبْلَ الْخُمُسِ