Why are there no Unit 6 to Unit 9 tutorials on learn.unity website?

I'm a beginer on unity.
I have found very good tutorials on "learn.unity"

I want to know why there are not "Unit 6" to "Unit 9" tutorials?

 

google shows these,
https://learn.unity.com/tutorial/unit-6-best-ui-practices-for-vr?courseId=5d955b5dedbc2a319caab9a0
https://learn.unity.com/tutorial/unit-9-optimizing-vr-apps?courseId=5d955b5dedbc2a319caab9a0

 

thank you very much!!!!
The search-inputbox that on "learn.unity" can't show those

 

Could you tell me how to seach them? What format does keyword look like?

I have tried but failed

 

looks like learn site search cannot find them(?)

i never use unity searches.. google is better,
https://www.google.com/search?q=site:learn.unity.com+unit+5

 

I get it, Thanks again!

 

This is a very late response, but for anyone who has the same question, Unit 6 is actually called “Next Steps”, and involves:

6.1 - Project Optimization
6.2 - Research and Troubleshooting
6.3 - Sharing your Projects
ECS Survival Guide

I finally found it by searching the “Create with Code” course on Unity Learn.