No extensions in extension manager

[lassoan (Andras Lasso)]

Thanks for reporting this. See explanation and temporary download link here:

2018.09.13: Only nightly Slicer packages - do not expect extensions this morning

Until the build infrastructure is restored, Slicer nightly version (with extensions) can be downloaded from here: https://download.slicer.org/?date=2018-09-10.