What is stub area in OSPF?
If we want to reduce the size of the routing table in all the routers in an area, then we can configure the area as a stub or totally stub area. For more information about totally stub area, please check the link.
In a stub area, you will not see the OSPF external routes (OE1 or OE2) or LSA 5 and LSA 4 in the routing table. Instead a LSA 3 default route (0.0.0.0/0) is advertised by ABR. This default route is originated by the ABR even though it does not have a default route.