As my “ERPNext Experience” started just a few months ago based on the first v13-beta-1, I have not a clear understanding on what the customer portal has been “before”, but my understanding (I just have upgraded my dev-instance to the v13-release version) is, that we still have the customer portal as shown in the screenshot from @backendo, the same as it has been there within the beta-branches.
In addition WebForms are still there (I am aware of the announcement [v13] Some proposed big changes to desk, routing and Web Forms - #20 by f_deryckel, but there was never a clear “answer”, also eg. Will the customer portal be part of the V13? did never find an answer.
So my understanding is, as of now, we still have a customer portal as well as web forms.
@charlie-cook, regarding where to set a default “landing page”:
