Drawn on the Dev Companion mark, which is a worked example and not the system's own. The steps are what this card documents — a drawing per size, each one on the pixel grid of that size, and what each step costs the interior. Every mark in the family takes them, including design-system-signet-*.svg.
Naive scalingone drawing at every size — what goes wrong
64
32
24
16
True at 32 and at 64, and nowhere between. At 24 the two-unit stroke lands on one and a half device pixels, so every line gets one hard edge and one soft one; at 16 the interior closes up and the three lines merge.
Optical sizesa drawing per size — 16 px is the floor
96
64
32
L · drawn at 32
Stroke 2, marker 10 × 13, three lines. The full statement, and it holds at 32, 64 and 96.
48
24
M · drawn at 24
Stroke 2 again, which in a smaller box is a heavier mark. The faint middle line goes: it was the one carrying the least.
32
16
S · drawn at 16 · favicon
Stroke 1, because sixteen pixels have nowhere to put two. The lines keep the ink the M is drawn with, so the mark gets heavier as the box shrinks rather than fainter.
16 px is the minimum. Below it, use the wordmark alone.
Three filesone per drawn size — the same way favicons are shipped
signet-l · 32
signet-m · 24
signet-s · 16
Media queries inside one SVG only see their own viewport when the file is linked, and not reliably across renderers — so the size is chosen where it is known: at the link.

<link rel="icon" sizes="16x16" href="signet-s.svg">

Every box is square, so one number sizes it and there is no aspect to state twice.