I installed Plone using the universal 5.2.4 installer in the account of a popular hosting company, and the development server works (on port 8080, when manually started).
The hosting company is providing Passenger as a mechanism to host WSGI apps; I created a simple passenger_wsgi.py script with an "application" function that returns "hello world" as plain text (on port 80).
So now I'd like to add the missing link between Plone and Passenger. How?
Update: I gave up on the idea, because shared hosting with Passenger is not appropriate for Plone.
I will instead manage a static web site with a simple admin, using Passenger to run it.