There is one course in the list of Courses for beta testing September 14 - September 22 (2020) which seems like the material is incomplete and thus, not ready to undergo beta testing.
Custom Models, Layers and Loss Functions, deeplearning.ai
Link to join the course: https://coursera.org/groups/beta-test-tf3-c1/invitation
Currently (15 Sep 2020), there is only one quiz in this course. No video contents and reading materials at all.
Best answer by Mohammad Sameer Hasan
Best Wishes to the team & of course you on testing it.