ns-ui / tabs-slack-cable — the underline is a cable, not a bar
ns-ui/registry is up to date. Last publish shipped 42 core components and 8 loud ones, all passing the screenshot verifier.
Click a tab — the cable pays out and sags across the jump, more for a far tab than a near one, then tautens flat with a small snap. Hover a tab you're not on and the nearest end tugs 3px toward it. Arrow keys, Home and End move focus and selection together.