This character is a Nonspacing Mark and inherits its script property from the preceding character.
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 acts as Nonspacing Mark. When changing direction it is not mirrored. U+0311 prohibits a line break before it. The glyph can be confused with one other glyph.
The Wikipedia has the following information about this codepoint:
Inverted breve or arch is a diacritical mark, shaped like the top half of a circle ( ̑ ), that is, like an upside-down breve (˘). It looks similar to the circumflex (ˆ), which has a sharp tip (Â â Ê ê Î î Ô ô Û û), while the inverted breve is rounded: (Ȃ ȃ Ȇ ȇ Ȋ ȋ Ȏ ȏ Ȗ ȗ).
Inverted breve can occur above or below the letter. It is not used in any natural language alphabet, but as a phonetic indicator. It is identical in form to the Ancient Greek circumflex.