Variant with 5 pins: a dual input dropout regulator (Globaltech GS1581D)
Package can have 3 pins with 90 mils (2.3mm) pitch or 5 pins with 45 mils (1.1mm) pitch. The middle pin is usually connected to the tab. The middle pin is sometimes omitted.
It is relatively common to find packages that contain other components than their designated ones, such as diodes or voltage regulators in transistor packages, etc.