version 1 .

; Assertion. Describes `object`.
Metadata = <metadata @object any @info { symbol: any ...:... }> .

; Projections of the `info` in a `Metadata` record.
Description = @present { description: IOList } / @invalid { description: any } / @absent {} .
Url = @present { url: string } / @invalid { url: any } / @absent {} .

; Data type. From preserves' `conventions.md`.
IOList = @bytes bytes / @string string / @nested [IOList ...] .