GNOME Bugzilla – Bug 788877
Add-ons -> Shell Extensions is empty
Last modified: 2017-10-28 13:45:51 UTC
3.26 branch Open the UI, navigate to Add-ons and then Shell Extensions. They're hidden because too many are returned (> 800), and there's a hard limit of 500 items in a category.
This problem has been fixed in the unstable development version. The fix will be available in the next major software release. You may need to upgrade your Linux distribution to obtain that newer version. https://git.gnome.org/browse/gnome-software/commit/?h=gnome-3-26&id=993faac