Blocks of text rewrap so that only one direction of scrolling is needed, e.g., for left-right and right-left scripts (languages), usually vertical scrolling and not horizontal scrolling.
Script direction: Rewrap above and Reflow below are written for left-right and right-left scripts for now for simplicity. We'll edit it to make it generic to apply also vertically to top-to-bottom scripts as appropriate — if we can without complicating it too much, or change it to example only.
- script vs. language reference says “Languages don't have a direction. Scripts have a writing direction”.