This character is a Other Letter and is mainly used in the Arabic script.
The glyph is not a composition. It has no designated width in East Asian texts. In bidirectional text it is written as Arabic letter from right to left. When changing direction it is not mirrored. The word that U+063A forms with similar adjacent characters prevents a line break inside it. The glyph can be confused with 21 other glyphs.
The Wikipedia has the following information about this codepoint:
The Arabic letter غ (Arabic: غَيْنْ, ghayn or ġayn) is the nineteenth letter of the Arabic alphabet, one of the six letters not in the twenty-two akin to the Phoenician alphabet (the others being thāʼ, khāʼ, dhāl, ḍād, ẓāʼ). It represents the sound /ɣ/ or /ʁ/. In name and shape, it is a variant of ʻayn (ع). Its numerical value is 1000 (see Abjad numerals). In the Persian language, it represents [ɣ]~[ɢ] and is the twenty-second letter in the new Persian alphabet.
Ghayn is written in several ways depending on its position in the word: