Operating system: Windows 10
Slicer version: 4.11.0-2020-07-18 r29221 / 26fbefd
Expected behavior: View and download extensions in Extension Manager
Actual behavior: No extensions are showing up:
The extensions server was replaced a few weeks ago. A compatibility layer was implemented but maybe it has some problem on that particular Slicer version. All the extensions should appear if you switch to the latest Slicer Preview Release.