Plugin Compatibility in the adapt-authoring wiki states:
"Your properties.schema
file is otherwise a standard json schema file defining the attributes that will be added to the course json output and read by your plugin."
Regarding "required", I'm seeing properties.schemas for contrib components that set the value as a boolean, (e.g., "required": true); yet http://jsonschema.net flags this as an error, wanting instead to see an array of properties that are required (e.g.,"required":[ "_supportedLayout", "_graphic", "_isResetOnRevisit" ]).
Is this non-standard use of a boolean value intentional?