tl;dr: Arabic typography's manuscript tradition justifies text by elongating letter strokes (kashida) rather than stretching word spaces, a system codified by 10th-century calligrapher Ibn Muqla and refined over centuries—but no modern browser implements it, falling back to ugly inter-word spacing. The author walks through the technical debt this creates: broken bidi cursor behavior, three competing digit systems, presentation-form encoding bugs that break search, and OpenType's unused `jstf` table. The entire functional Arabic web rendering stack (HarfBuzz, Amiri font) was built largely by a handful of unpaid volunteers, while browser vendors have contributed essentially nothing to solving justification.