Ok, correction:
It does show some extensions from
extensions.gnome.org, but it's just a
subset. In my case, Software shows 55 extensions in total (both from
RPMs and
extensions.gnome.org) compared to ~190 on the website. Is
there any filter?
I have two F25 installations, both upgraded. In both I see the same 27 extensions
available, all of them packaged in Fedora.
In a clean installation, I see 52 extensions (out of 187 extensions available on the
website).
So something seems seriously broken in both cases.