I have two questions. I found ClamTK in the Software Center. Is this just a GUI for ClamAV or is ClamAV included?
Secondly, there are many websites that say ClamAV can be downloaded from the Software Center. Example: https://help.ubuntu.com/community/ClamAV
I am unable to find it in the Software Center. Does that mean that it was removed? If so, why?
clamav is still available in the repositories. Simply install it via sudo apt-get install clamav.
It appears that the software-center(s) [especially gnome-software] do not show all packages - I believe it actually only shows packages with graphical user interfaces.
ClamTK is a graphical front-end for ClamAV and pulls along the needed packages as clamav on installation.
If you want a full blown "old-school" graphical package manager I recommend you to go with Synaptic.
