This character is a Math Symbol and is commonly used, that is, in no specific script.
The glyph is not a composition. Its East Asian Width is narrow. In bidirectional text it is written as European number separator from left to right. When changing direction it is not mirrored. U+002B prohibits a line break after it, if it is followed by a number. The glyph can be confused with 10 other glyphs.
The CLDR project calls this character “plus sign” for use in screen reading software. It assigns these additional labels, e.g. for search in emoji pickers: add, plus.
The Wikipedia has the following information about this codepoint:
The plus sign (+) and the minus sign (−) are mathematical symbols used to denote positive and negative functions, respectively. In addition, + represents the operation of addition, which results in a sum, while − represents subtraction, resulting in a difference. Their use has been extended to many other meanings, more or less analogous. Plus and minus are Latin terms meaning "more" and "less", respectively.