Virtual Box Guest Additions with APT requirements.
When using Debian or other APT based systems, the guess additions can improve the experience by providing graphical drivers and adjustments to X that allow changing resolutions. (All commands require elevation of privilege). First we must insure the header files are available
apt-get install -y linux-headers-$(uname -r)
and then we go to the Devices menu of VirtualBox and select Insert Guess Additions CD. Finally
and in that folder