System Information
Operating system: MacOS 10.14.5
Graphics card: AMD

Blender Version
2.80rc1
Broken: (example: 2.80, edbf15d3c044, master, 2018-11-28, as found on the splash screen)
Worked: (optional)
This was working: 2.80.0-git20190711.bb7b741d2f1c-x86_64

Short description of error

In 2.80RC1 there are no addons and no way to add them.

Exact steps for others to reproduce the error
Based on the default startup or an attached .blend file (as simple as possible).