The glyph is not a composition. It has no designated width in East Asian texts. In bidirectional text it is written from left to right. When changing direction it is not mirrored. The word that U+04AF forms with similar adjacent characters prevents a line break inside it. The glyph can be confused with one other glyph.
The Wikipedia has the following information about this codepoint:
Ue or Straight U (Ү ү; italics: Ү ү) is a letter of the Cyrillic script. It is a form of the Cyrillic letter U (У у У у) with a vertical, rather than diagonal, center line. Whereas a standard Cyrillic U resembles a lowercase Latin y, Ue instead uses the shape of a capital Latin Y, with each letter set higher or lower to establish its case. The lower case resembles the lower case of the Greek letter Gamma.
Ue is used the alphabets of the Bashkir, Buryat, Kalmyk, Kazakh, Kyrgyz, Mongolian, Sakha, Turkmen, Tatar and other languages. It commonly represents the front rounded vowels /y/ and /ʏ/, except in Mongolian where it represents /u/.
In Tuvan and Kyrgyz the Cyrillic letter can be written as a double vowel.