Long story short, I have rooted my phone in order to resolve 'low on internal storage' issues (turned out the cache folder grew to almost 2GB). I have used kingoroot as suggested in this answer and it worked nicely.
However, shortly after the rooting, I noticed I had a new lockscreen I've never seen before:
Before the rooting I had what I believe is the official Android lockscreen, where you slide your finger from the center of the screen to a lock icon, camera, or unread messages if you have any.
I certainly don't remember installing a lockscreen app, but after rooting and cleaning the internal storage I finally was able to install updates in Google Play, and there were quite a few of these.
How can I find out where did this lockscreen came from? Is this how Android lockscreen looks now on Android 4.4.2? If not, is it expected to get unwanted software when I root my phone? And finally, how do I uninstall it?
Edit: the method for replacing KingoRoot with SuperSU didn't work. I've got error messages about non-existing files, and SuperSU started but couldn't update the binary.