kinfocenter is an application in Plasma where you can see all kinds of information about your system. So no, they are not just adding k to random words like quantum in Ant-man. :)
hyprwayland-scanner-git is also an AUR package, so pacman can't install that. You need to install it with some other means, like makepkg, yay, paru etc, before installing hyprland-git.
I have been pretty lucky with the Aqara plugs. I have like 8-10 of them at this point and they work really well with homeassistant, giving energy readings and such.
Well, whoever is developing it should publish the code somewhere...