The box behind huuu.nl, on the kind of amber dot-matrix display a Saab shows between the dials. It reads the machine's own vitals every few seconds: uptime, load, processor, memory, disk and temperature. The stalk cycles the pages, and the Night Panel works like the real thing.
SID is the Saab Information Display, the little dot-matrix screen in the middle of the dashboard of a Saab 9-3 or 9-5. It shows the clock, the radio, the trip computer and the car's warning messages, one terse line at a time. This is the same idea, pointed at a server instead of a car. The characters are drawn as real dots, lit amber on an unlit grid, the way the original display works.
Saab's Night Panel button switched off everything on the dashboard except the speedometer, on the theory that at night you don't need the rest and the dark is easier on the eyes. Anything important would light back up on its own. The button here does the same: it blanks the display down to a single dim line, until something needs saying or you touch the stalk.
A small script on the box reads /proc and /sys — the files Linux uses to report its own state — and hands back the totals. Nothing identifying is on this page: no addresses, no accounts, just how hard the machine is working. If the temperature line is missing, this particular box has no sensor the kernel exposes.