Belarusian Arabic alphabet
The Belarusian Arabic alphabet or the Belarusian Arabica was based on the Perso-Arabic script and was developed in the 15th or 16th century. It consisted of 28 graphemes, including several additions to represent Belarusian phonemes not found in the Arabic language.
Source: Wikipedia — Belarusian Arabic alphabet (CC BY-SA 4.0)