so that the database registers itself with the listener (saves you having to have a listener.ora with services in it)
now what s written there is the "defaut" port 1521 on the localhost, but if you use a different port then you need to update this parameter
*.local_listener='(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=127.0.0.1 )(PORT=1521)))'
what is the advantage of putting this Listener.ora line in the init.ora?