Aspire 5.0 had a major architecture re-design, compared to its predecessors Aspire 3.x and 4.x, for the purpose of tackling the most common source of complexity in managing Aspire deployments: configuration, availability, and coordination of crawl execution.
The biggest change you would notice compared to prior versions is that there isn't a content-source anymore. The configuration of crawls has been split into re-usable entities with relationships to one another.
What used to be called a "content-source" now is a collection of related configuration objects:
In this new approach of configuration, you can configure everything only once and reuse them to create multiple seeds for the same source repository. So if you need to change the credentials, you don't have to do it on all seeds but rather on the credentials object only, and all seeds related to it will be affected.
Another big change is the introduction of a manager/worker architecture, where the manager nodes coordinate configuration, crawls and failure recovery, and the worker nodes only care about executing jobs (representing documents)