There are several threads in this forum (here or here or here) listing the same issue with the Adobe Extension Manager CC: installed products don’t show or extensions fail to install. Then I found this Adobe announcement from June 2015 that the Extension Manager is being discontinued. As a make-shift replacement, it seems that the ExMan command line tool is still supported (and yet seems to fail to install my developed extension locally).
My questions now are:
How do I test-deploy a locally developed and signed extension (for Adobe InDesign)?
How does a customer manage their extensions, and in particular, is supposed to install mine?
Are third-party tools like the ZXP Installer viable and recommended alternatives?