This character is a Uppercase Letter and is mainly used in the Adlam script. Its lowercase variant is Adlam Small Letter Ba.
The glyph is not a composition. It has no designated width in East Asian texts. In bidirectional text it is written from right to left. When changing direction it is not mirrored. The word that U+1E904 forms with similar adjacent characters prevents a line break inside it.
El Wikipedia tiene la siguiente información acerca de este punto de código:
The Adlam script is a script used to write Fulani. The name Adlam is an acronym derived from the first four letters of the alphabet (A, D, L, M), standing for Alkule Dandayɗe Leñol Mulugol (𞤀𞤤𞤳𞤵𞤤𞤫 𞤁𞤢𞤲𞤣𞤢𞤴𞤯𞤫 𞤂𞤫𞤻𞤮𞤤 𞤃𞤵𞤤𞤵𞤺𞤮𞤤), which means "the alphabet that protects the peoples from vanishing". It is one of many indigenous scripts developed for specific languages in West Africa.
Adlam is supported in Google's Android and Chrome operating systems. There are also Android apps to send SMS in Adlam and to learn the alphabet. On computers running Microsoft Windows, the Adlam script was natively supported beginning with Windows 10 version 1903, which was released in May 2019. On macOS, the Adlam script was natively supported beginning with Ventura in 2022.