Icon ink
A mark’s painted ink inside its tile: 0.58 of the tile, measured, not scaled by eye.
The specimen
The part is in review for the next Shared release; the specimen is here so the design can be seen.
The app tile uses a 0.58 painted-ink fraction of the tile, measured from the painted bounds rather than the viewBox; the icon set is normalised to one ink size so a glyph from any set sits the same beside another. Small glyphs draw their solid form; nothing is scaled by eye.
What shipped
4.183.0 gave every shape glyph a solid drawing at 18 px and under. The normalisation in review measures every shared icon set in Chrome, normalises 666 drawings to one ink size (0.79), and uses a 0.58 painted-ink fraction for app tiles; the old oversized tile rule is gone.
“Use a 0.58 painted-ink fraction for app tiles and remove the old oversized tile rule.” — the change, with the 50/58/64% comparison sheet
The rules it carries out
2 An icon name is checked against the set that draws it.96 The Pair is the only mark, and it does the waiting.46 Everything you can press is at least 44 px.
Build it
// openvibe-shared/app-icon.js: the favicon's heavy form on a rounded tile
favicon({ site }) // mark(site, 0.58, 'heavy')
// the test measures the painted bounds in headless Chrome, not the viewBox:
test/icon-ink.test.js // ink within 4% of the target, centre within 3%