gdk:monitor-manufacturer (object)

object -- a gdk:monitor object
manufacturer -- a string for the name of the manufacturer, or nil

The accessor for the manufacturer slot of the gdk:monitor class gets the name or PNP ID of the monitor's manufacturer, if available. Note that this value might also vary depending on actual display backend. PNP ID registry is located at https://uefi.org/pnp_id_list.