The glyph is not a composition. Its width in East Asian texts is determined by its context. It can be displayed wide or narrow. In bidirectional text it is written from left to right. When changing direction it is not mirrored. The word that U+00E6 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:
Æ (lowercase: æ) is a character formed from the letters a and e, originally a ligature representing the Latin diphthong ae. It has been promoted to the status of a letter in some languages, including Danish, Norwegian, Icelandic, and Faroese. It was also used in Old Swedish before being changed to ä. The modern International Phonetic Alphabet uses it to represent the near-open front unrounded vowel (the sound represented by the 'a' in English words like cat). Diacritic variants include Ǣ/ǣ, Ǽ/ǽ, Æ̀/æ̀, Æ̂/æ̂ and Æ̃/æ̃.
As a letter of the Old English Latin alphabet, it was called æsc, "ash tree", after the Anglo-Saxon futhorc rune ᚫ which it transliterated; its traditional name in English is still ash, or æsh (Old English: æsċ) if the ligature is included.