Am 2017-02-28 10:20, schrieb René J.V. Bertin:
What component(s) might be involved? Who's responsible for the screensaver and screen/session locking? Is there a way to get an on-screen keyboard in the session unlock screen?
As you should be aware of: kde4 has been unmaintained for years and is EOL. Given that there is nobody "responsible" for that. The screensaver infrastructure in KDE4 has been unmaintained for at least five years now.
I have no idea whether it's possible to get an on-screen keyboard. It should be impossible, the lock screen architecture should prevent that.
Cheers Martin