Well, you can at least connect to it from SSDT.
Choose Tools/SQL Server/New Query and then expand the 'local' node to select the connection you are interested in.
When I did this and ran
SELECT @@SERVERNAME
I got some nonsense back (machine name\LOCALDB#90ACA499).
So I tried connecting to that in SSMS, but the connection was unsuccessful (received a generic 'cannot connect to ...' error).
If you haven't even tried to resolve your issue, please don't expect the hard-working volunteers here to waste their time providing links to answers which you could easily have found yourself.