Grapheme Cluster Break - Prepend

Prepend is a classification for certain characters, mostly Arabic and Syriac script marks, that appear before their base character in visual order but are logically stored after it in text. This value ensures that such a mark is treated as part of the same grapheme cluster as the following base character, rather than as an independent cluster, preventing unintended breaks during line wrapping, cursor movement, or text selection. It only applies when the mark directly precedes a base character that is not a control or spacing combining mark, and it does not affect clusters where the mark is separated by other intervening characters. Prepend effectively keeps the mark visually attached to the next symbol, preserving the intended written form.