This character is a Other Letter and is mainly used in the Buginese script.
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+1A15 forms with similar adjacent characters prevents a line break inside it.
The Wikipedia has the following information about this codepoint:
The Lontara script (ᨒᨚᨈᨑ), also known as the Bugis script, Bugis-Makassar script, or Urupu Sulapa’ Eppa’ "four-cornered letters", is one of Indonesia's traditional scripts developed in the South Sulawesi and West Sulawesi region. The script is primarily used to write the Buginese language, followed by Makassarese and Mandar. Closely related variants of Lontara are also used to write several languages outside of Sulawesi such as Bima, Ende, and Sumbawa. The script was actively used by several South Sulawesi societies for day-to-day and literary texts from at least mid-15th Century CE until the mid-20th Century CE, before its function was gradually supplanted by the Latin alphabet. Today the script is taught in South Sulawesi Province as part of the local curriculum, but with very limited usage in everyday life.
Lontara is an abugida with 23 basic letters. The script is a descendant of Brahmi through Kawi intermediaries. As of other Brahmic scripts, each letter represents a syllable with an inherent vowel /a/, which can be changed with diacritics. The direction of writing is left to right. Traditionally, the script is written without word breaks (scriptio continua) and with little to no punctuation. A typical Lontara text may contain a lot of ambiguities as Coda syllables, or consonants at the end of syllables, are normally not written and must be supplied by readers from context.