Chapter: visual
Rule: scanline
Spec: Broken scanline
Repeating items or form chrome do not share an edge. Scanning becomes hunting.
List/table row edges, tab titles, form fields on a row, or a header vs its cells. Nested nav indent, masonry, two-column details grids (each field already has a row partner), and a Search-row ⌘K / Ctrl+K (<kbd> or ml-auto shortcut chip) are not this.
This id is stable. Reports link here so T/V/Q classes do not shuffle when a soak ranks differently.