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+030B prohibits a line break before it. The glyph can be confused with 4 other glyphs.
The Wikipedia has the following information about this codepoint:
The double acute accent (◌̋) is a diacritic mark of the Latin and Cyrillic scripts. It is used primarily in Hungarian or Chuvash, and consequently it is sometimes referred to by typographers as hungarumlaut. The signs formed with a regular umlaut are letters in their own right in the Hungarian alphabet—for instance, they are separate letters for the purpose of collation. Letters with the double acute, however, are considered variants of their equivalents with the umlaut, being thought of as having both an umlaut and an acute accent.