rosa@debian:~$ sudo apt install virtualbox-6.1
Reading package list... Done
Building dependency tree... Done
Reading state information... Done   
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 virtualbox-6.1 : Depends: libvpx6 (>= 1.6.0) but it is not installable
                  Recommends: libsdl-ttf2.0-0 but it is not going to be installed
                  Recommends: linux-headers-generic oppure
                              linux-headers-generic-pae but it is not installable or
                              linux-headers-686-paebut it is not installable or
                              linux-headers-amd64 ma non sta per essere installato or
                              linux-headers-2.6-686 but it is not installable or
                              linux-headers-2.6-amd64 but it is not installable or
                              linux-headers but it is not installable
                  Recommends: linux-image but it is not installable