UFO

Rig names editable-font meaning as rig.font.*. Unified Font Object files stay host mappings at the boundary - same rule as IFC in openbim.md and SVG (design philosophy).

The Contract job is entities, POD components, and schema ids. A .ufo / .ufoz reader (RigKit rigUfo or a sibling tool) is fulfillment, not this catalog.

Thin layer

We do not invent rig.font.ttf or treat a compiled OT/TTF as the source face. A file on disk is rig.media.asset_ref kind font. A canvas run that uses a compiled face is rig.media.text. Outlines compose rig.geometry.path on the glyph entity - do not add a second contour type.

UFO idea	Rig
Family / style / UPM / metrics	`rig.font.face`
Layer (`public.default`, ...)	`rig.font.layer` + `rig.meta.named`
Glyph name	`rig.meta.named` `stableId`
Unicodes / advance width	`rig.font.glyph`
Contours	`rig.geometry.path` on the glyph
Component (composite)	`rig.font.component` on a child entity
Anchor	`rig.font.anchor` on a child entity
`kerning.plist` pair	`rig.font.kern` (`left` / `right` are names)
`groups.plist`	`rig.font.group`
`features.fea`	`rig.media.code` `language` `fea`, pointed at by `face.features`
`fvar` axis	`rig.font.axis` (child of face)
`avar` map	`rig.font.avar` on the axis entity
Live lattice / morph cell	`rig.font.cell` on the glyph (default path stays on `geometry.path`)
Containment	`rig.spatial.relationship` `parent` (face, layer, glyph; face, axis)

Encodings (fulfillment)

File	Role
`.ufo` / `.ufoz`	Map into / out of `rig.font.*` + path
`.glif`	One glyph; same POD as `rig.font.glyph` + path / component / anchor
`.otf` / `.ttf` / `.woff2`	Compiled instance - asset_ref or export, never the live source

Do not put glyph caches, atlas slots, dirty epochs, or FreeType handles in portable components.

Host trips!

Two hosts that speak rig.font.face + glyph + kern can exchange a UFO-as-Rig document. Round-tripping every lib.plist key or UFO3 guideline is not required. Hosts that morph add axis / avar / cell.

Examples: examples/font-ufo.json, examples/font-var.json.