@SarpSTA Yes, that's right. The su on Unix machines doesn't have a GUI: it works out permissions from a text file. And the stock Android one has pretty trivial access control.
oh wait, that's stupid
su doesn't use a text file: I'm thinking of sudo, which has /etc/sudoers. su just uses a special group.
@Firelord Yeah. And I start thinking those users played with "secret codes". I remember having done that years ago, with exactly those results: strange numeric apps turning up in app usage.
@Firelord Definitely was that for me. And I even was that lucky that only a factory-reset reverted it. Since then I've stopped "playing" with those too much :)