From the official systemd webside:

Yes, it is written systemd, not system D or System D, or even SystemD. And it isn't system d either. Why? Because it's a system daemon, and under Unix/Linux those are in lower case, and get suffixed with a lower case d. And since systemd manages the system, it's called systemd. 

https://wiki.freedesktop.org/www/Software/systemd/

Both, systemd kcm here in kde.bugs.org and in systemsettings use currently the spelling with the huge S 

In systemsettings5 lead this to the situation, that systemd appears two times in the search box

http://funkyimg.com/i/2bkTa.png

http://funkyimg.com/i/2bkT4.png

http://funkyimg.com/i/2bm3m.png

Reproducible: Always


Actual Results:  
2 entrys of systemd in systemsettings5

Expected Results:  
one entry of systemd in systemsettings5