Fitrah (Zakat al-Fitr) is a kaffarah for fasting person's unbefitting speech

The Messenger of Allah ﷺ prescribed Zakat al-Fitr as a purification ˹and a kaffarah (expiation)˺ of the fasting person for any empty and obscene talk and ˹for it to be˺ as food for the needy. If anyone pays it before the ˹Eid˺ prayer, it will be accepted as zakat. If anyone pays it after the prayer, that will be a sadaqah like other sadaqahs.  

فَرَضَ رَسُولُ اللَّهِ ﷺ زَكَاةَ الْفِطْرِ طُهْرَةً لِلصَّائِمِ مِنَ اللَّغْوِ وَالرَّفَثِ وَطُعْمَةً لِلْمَسَاكِينِ مَنْ أَدَّاهَا قَبْلَ الصَّلاَةِ فَهِيَ زَكَاةٌ مَقْبُولَةٌ وَمَنْ أَدَّاهَا بَعْدَ الصَّلاَةِ فَهِيَ صَدَقَةٌ مِنَ الصَّدَقَاتِ