getSupplementalDescription
Returns the supplemental description of this AccessibilityNodeInfoCompat.
A supplemental description provides brief supplemental information for this node, such as the purpose of the node when that purpose is not conveyed within its textual representation. For example, if a dropdown select has a purpose of setting font family, the supplemental description could be "font family". If this node has children, its supplemental description serves as additional information and is not intended to replace any existing information in the subtree. This is different from the getContentDescription in that this description is purely supplemental while a content description may be used to replace a description for a node or its subtree that an assistive technology would otherwise compute based on other properties of the node and its descendants.
Return
The supplemental description.