The spec says that a link can be either a string or an object.

However the schema enforces that self links must be strings.

(It is also a bit odd that the properties and descriptions in definitions/links seems to be relationship-specific, but this definition is referenced from resource and top level link objects.)

I was wondering if the self links are an exception and must be strings intentionally, or is it a bug in the schema? If it's the latter I'd be happy to open a PR to fix the schema.

Sample use case: on a project I'm working on we prefer links as objects v.s. links. We have a convention to pass extra meta data for each link e.g. request header, http verb (GET/PUT/POST) and so on. However the schema validations fail if a resource selflink is an object, even though there doesn't seem to be anything in the documentation that makes self links exceptional.