[VR] Repo's Difference or Alternatives.

Hello
Environment : RHEL 8
Umm.. to install any high-end application, normally in RHEL 7 we enable the "Extra, Supplementary and Optional" repo's right.
But in RHEL 8 we have App-Stream repos. I'm actually confused by that. Like are there no Extras or Supplementary or Optional Repo's in RHEL 8?
Could you please explain it?

Thank You.