Yes, installed; just like the gvfs and fuse components. On my older (to be sold) desktop, I can just click Network -> Shared Folders (SMB), and then I'll see all the computers on the network, including the new desktop. However, on the new desktop, this shows no computers, except itself.

The new desktop can reach all the other shares, though by smb://hostname.local/share.

If Lemmy stays as it is, it won't work. The two largest Lemmy instances seem to be Lemmy.world and Lemmy.ml. I've been able to sign up on Lemmy.world and Feddit.nl (because it's local to me), but not on Lemmy.ml, where the KDE community actually is, because my sign-up still has to be approved (no e-mail with more information or anything.). So first, I have to use the KDE community at Lemmy.ml through another instance and second, my subscription to the KDE community has been pending for days now. Third, it's entirely possible to have 2-3-4-5 KDE communities scattered over multiple instances, but they are all "Lemmy".

"Normal" people are never going to use this. It's way too complicated for them, and federation is too slow if the community you want to subscribe to is on a slow or overloaded instance.