SFSafariToolbarItem
A proxy for a Safari app extension toolbar item in a Safari window.
Declaration
class SFSafariToolbarItemOverview
Your app extension only uses this object when it wants to explicitly set the toolbar item state. Typically, other state changes occur automatically. Safari calls validateToolbarItem(in:validationHandler:) on your app extension handler when changes, such as navigation to a webpage, could affect the state of the toolbar item.