As you get deeper into your journey using Ansible, you might start filing issues on GitHub, chatting in #ansible on Freenode IRC, or otherwise interacting more with the Ansible community. Because the Ansible community has grown tremendously over the years—and as Ansible has been subsumed by Red Hat, which has various support plans for Ansible—there's been a greater distinction between parts of Ansible that are 'core' (e.g. maintained by the Ansible Engineering Team) and those that are not.
When everything works, and when you're living in a world where security and compliance requirements are fairly free, you would never even care about the support for Ansible components (modules, plugins, filters, Galaxy content). But if something goes wrong, or if there are security or compliance concerns, it is important to be able to figure out what's core, what's 'certified' by Red Hat, and what's not.