Hi,
I discovered accidentally this morning that - the moment you start typing something at the desktop - automatically a search starts based on the typed characters. This is THE fastest way to start an application without touching the mouse!
Really gr8 feature.
Please never sacrifice this one EVER for anything!
Regards Frank
There isnt any information as to what desktop you are using.
But this is a feature/option of KDE (krunner) that I believe is enabled by default.
(I actually dislike it and have it disabled)
I was going to say the same thing, but you beat me to it. 
I have it enabled, because it only works like that on an empty desktop, or if no application window has the focus. If there is an application window in focus, you have to press Alt+F2 or Alt+Space — I’ve changed the latter here to Meta+Space instead.
Well, as @cscs said, this is a feature of the KDE Plasma desktop environment itself — possibly with an equivalent functionality in the GNOME desktop environment, although I’m not sure of that — so this is not something that Manjaro can take credit for. 
As an aside, your name appears to be Vlaams — and your first name is the same as mine. It’s good to see more Belgians around this neck of the woods.
I am from Limburg (Sittard) where my name is so common - half the city will look up if you call my name out loud 
Sorry for the off-topic reply