gui.fonts

The font families a style.fontFamily can select.

Each row carries the family key, the aliases that select the same group (web-font names, CSS generic families, the face names registered under it), the concrete faces in the regular / bold / italic / boldItalic slots, more (the other faces sharing those slots, such as the installed chunks of an on-demand face, each drawing the codepoints the slot's face lacks), and system, true when the family came from the host OS rather than a bundled .font asset. A family whose faces load on demand lists the chunks installed so far; font.onDemand() lists every chunk and its state.

A host-OS family renders on the machine that has it and nowhere else, and there are no OS fonts on WASM, so a UI meant to look the same everywhere selects a family with system = false — which is what this tool returns unless you ask for the rest.

A fontFamily naming a family absent from this list paints in the default proportional face, and gui.validate reports it as unknown-font-family for the screen once that screen has painted.