It's a bit of split as to how Red Hat considers the term "documentation". The actual product docs are free to access while the Knowledge Base, which is consider

It's a bit of split as to how Red Hat considers the term "documentation". The actual product docs are free to access while the Knowledge Base, which is considered a value-add for customers, does have a lot of its content (usually troubleshooting or specific instructions/guides) behind either a Red Hat login or needing an active subscription. For which, as you mentioned, the Developer Subscription for Individuals qualifies.