Line Break - Contingent Break Opportunity

Contingent Break Opportunity is a special line breaking class that applies only to certain characters, like the Tibetan mark “་” (U+0F0B) or the Arabic comma, which act as potential break points only when no other break opportunity exists in the surrounding text. This means the character allows a line to break at its position, but only as a last resort, if the text would otherwise overflow without any valid break elsewhere on the line. It is weaker than a normal break opportunity, so the rendering engine first tries to break at earlier or later allowed points, and only if none are available does it use the contingent one to prevent an unsightly overlong line. This behavior helps maintain readability in scripts with dense spacing rules.