Error: No formatter registered for type json:number

[Monoakuma]

Crash report

• Page url: https://misode.github.io/worldgen/density-function/
• Generator ID: worldgen/density_function
• Current version: 1.20
• Latest version: 26.3-snapshot-2

Stack trace

Error: No formatter registered for type json:number
    at z$ (../../node_modules/@spyglassmc/core/lib/processor/formatter/builtin.js:3:10)
    at formatter (src/app/services/Spyglass.ts:223:9)
    at (unknown) (src/app/components/generator/SchemaGenerator.tsx:116:19)

Appeared while trying to load a project from .zip I don't think I've done anything. Browser is Firefox.