Control keys and automatic startup of programs at login

A while ago, using Leap 42.2, I did a key stroke combination like superkey alt F5, which popped up a small window in the top center of the desktop.
I cannot duplicate that series of key strokes.
Clicking on that window opened a “list editor” where you could add programs that you want to start automatically at login.

What is that list-editor called and how do I open it again?

Thank you.

As you say you click, etc., I assume this is done in a GUI login.

Please can you explain which desktop you use so people can try to reconstruct what you did?

My bad.

I’m using KDE.

I don’t know what keys you originally used.

If I want a program to automatically start on login to KDE, I use:

Configure Desktop → Startup and Shutdown → Autostart