Questions relating to the Arabic language, fonts ... or even other languages which use Arabic script like Persian, Urdu...
Consider adding RTL tag if it is common with Right-to-Left languages (BiDirection, Shaping, Display...), and Unicode tag if it is common with language written using Non-ASCII letters (Unicode input,...)
Unlike other RTL languages (ex: Hebrew), Arabic is a cursive script. Letters are written connected so same letter may have more than 4 glyphs as some combinations has specific glyphs. So Arabic has additional specific issues. Such example, Arabic text should be in the normalized form before processing (Indexing...)