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+0628 forms with similar adjacent characters prevents a line break inside it. The glyph can be confused with 36 other glyphs.
The Wikipedia has the following information about this codepoint:
Bet, Beth, Beh, or Vet is the second letter of the Semitic abjads, including Phoenician bēt 𐤁 , Hebrew bēt ב, Aramaic bēṯ 𐡁, Syriac bēṯ ܒ, and Arabic bāʾ ب. Its sound value is the voiced bilabial stop ⟨b⟩ or the voiced labiodental fricative ⟨v⟩.
The letter's name means "house" in various Semitic languages (Arabic bayt, Akkadian bītu, bētu, Hebrew: bayīṯ, Phoenician bēt etc.; ultimately all from Proto-Semitic *bayt-), and appears to derive from an Egyptian hieroglyph of a house by acrophony.
The Phoenician letter gave rise to, among others, the Greek beta (Β, β), Latin B (B, b) and Cyrillic Be (Б, б) and Ve (В, в).