A coder factory found in a package's public types.
name: string
The exported name, e.g. pngFile.
optional
decodedType: string
The T of Coder<T>, absent when it is an anonymous type such as a union.
optional
summary: string
First line of the factory's JSDoc, absent when it is undocumented.
requiredParams: number
Arguments the caller must supply; 0 means the CLI can call it directly.