ثُمَّ يُكَبِّرُ تَكْبِيرَةً ثَالِثَةً، يَدْعُو فِيهَا لِنَفْسِهِ، وَلِلْمَيِّتِ، وَلِلْمُسْلِمِينَ.
Translation: Then a third takbir is said, followed by supplication for oneself, the deceased, and Muslims.
Supplication after the third takbir is central to the funeral prayer. The source explicitly identifies three beneficiaries: the worshipper, the deceased, and Muslims generally.
It is a prayer for divine mercy and forgiveness, not an independent rakʿah or a Qurʾanic recitation requirement.