U+2423 Open Box

The Wikipedia has the following information about this codepoint:

A whitespace character is a character data element that represents white space when text is rendered for display by a computer.

For example, a space character (U+0020   SPACE, ASCII 32) represents blank space such as a word divider in a Western script.

A printable character results in output when rendered, but a whitespace character does not. Instead, whitespace characters define the layout of text to a limited degree – interrupting the normal sequence of rendering characters next to each other. The output of subsequent characters is typically shifted to the right (or to the left for right-to-left script) or to the start of the next line. The effect of multiple sequential whitespace characters is cumulative such that the next printable character is rendered in a location based on the accumulated effect of preceding whitespace characters.

The term whitespace is rooting in the common practice of rendering text on white paper. Normally, a whitespace character is not rendered as white. It affects rendering, but it is not itself rendered.