It's certainly related. In very general terms, I would say splitting a Rails app into multiple engines is the same pattern as umbrella applications.

However, there are more interesting specifics here about things like all engines sharing a database, but having exclusive ownership of tables, as well as splitting HTTP routing over multiple engines etc.

I think you'll also find a lot of conceptual overlap with Phoenix Contexts; they'll generally all start as part of the same monolith/app but are sufficiently discrete that you can separate them out more easily than the Rails situation in TFA.

Am I the only one who has a distaste for this phrase "component based development"? It just seems like a fancy way of saying object oriented programming without an overarching design pattern.