I don't remember downloading a different desktop management environment (DM), so I'm using only Unity.
Why do I have updates for Dolphin (A KDE file manager) and Konqueror (A KDE web browser) ?
I'm mean why do I have them installed in the first place ?
EDIT
The answers suggest that I may have downloaded tools with KDE dependencies. If that's true, why would this include main applications such as text-editors and web browsers in the updates ?
This is the output of some of the suggested commands to investigate:
$ dpkg --get-selections | grep kde
kde-baseapps-bin install
kde-baseapps-data install
kde-l10n-engb install
kde-runtime install
kde-runtime-data install
kdelibs-bin install
kdelibs5-data install
kdelibs5-plugins install
libkde3support4 install
libkdeclarative5 install
libkdecore5 install
libkdesu5 install
libkdeui5 install
libkdewebkit5 install
$ apt-cache rdepends kde
<kde>