devel branch FTBFS since virtualbox 6.0.14-dfsg-1 was uploaded to sid and linux-image-5.3.0-trunk-amd64 is not in experimental anymore
This does not affect our testing branch, that'll be used to build Tails 4.0, yet. But if we have to bump the APT snapshots there for 4.0 (e.g. for #17124), then we'll have a problem there too, hence target version = 4.0 and priority >> normal.
sid now has 6.0.14-dfsg-1, and virtualbox-guest-x11 6.0.14-dfsg-1 depends on
a newer libc6 than the one we have in Buster. So for now, let's stick
to an older version, which seems preferable than fully removing this package.
A cleaner solution would be to maintain a custom backport of src:virtualbox.
Last time anonym and I discussed how much resources we wanted to spend into
VirtualBox support, we decided to do it on a best effort basis, i.e. to install
it from sid when it's possible, and to drop it when it's not possible anymore.
I'm already doing a bit more than that here, so maintaining a custom backport
seems unreasonably expensive to me.
We shall reconsider once we add Secure Boot support (the dkms module won't
be loadable anymore) or when VirtualBox has a severe security issue.