Block from U+FB50 to U+FDFF. This block was introduced in Unicode version 1.1 (1993). It contains 643 codepoints.
The Wikipedia provides the following information on block Arabic Presentation Forms-A:
Arabic Presentation Forms-A is a Unicode block encoding contextual forms and ligatures of letter variants needed for Persian, Urdu, Sindhi and Central Asian languages. The presentation forms are present only for compatibility with older standards, and are not currently needed for coding text.