A plain object with properties:
isCaptionOptional [type: Boolean] - True to indicate that the caption is optional.
A collection of data alignable items in the adapter. Structure:
alignToSelf [type: Boolean] - A value indicating whether the axis should align to other instances of itself when used in a repeater.
caption [type: String, optional: true] - The caption for the alignable item, which may be optional if indicated.
data [type: String] - The stringified version of the underlying alignable item.
object [type: Object] - The underlying object which is alignable.