Eu segui vários guias, por exemplo,
https://computingforgeeks.com/install-virtualbox-ubuntu-debian/
https://tecadmin.net/install-virtualbox-on-debian-10-buster/
Na etapa:
apt install virtualbox-6.0
Ele falha com:
root@debian:~# apt-get update
Hit:1 http://deb.debian.org/debian buster InRelease
Hit:2 http://deb.debian.org/debian-security buster/updates InRelease
Hit:3 http://deb.debian.org/debian buster-updates InRelease
Hit:4 http://download.virtualbox.org/virtualbox/debian stretch InRelease
Get:5 https://download.virtualbox.org/virtualbox/debian buster InRelease [7,733 B]
Get:6 https://download.virtualbox.org/virtualbox/debian buster/contrib amd64 Packages [1,521 B]
Fetched 9,254 B in 2s (4,145 B/s)
Reading package lists... Done
root@debian:~# apt-get install virtualbox-6.0
Reading package lists... Done
Building dependency tree
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-6.0 : Depends: libcurl3 (>= 7.16.2) but it is not installable
Depends: libvpx4 (>= 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 but it is not installable or
linux-headers-generic-pae but it is not installable or
linux-headers-686-pae but it is not installable or
linux-headers-amd64 but it is not going to be installed 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
E: Unable to correct problems, you have held broken packages.
Eu tentei instalar essas dependências manualmente, mas se eu tentar instalar o libcurl3, ele me diz que só posso instalar o libcurl4. Se eu instalar libcurl4, não parece afetar nada, pois requer libcurl3 e não 4.