Installation de virtualbox depuis testing, dépendances étranges

Bonjour à tous,

Je dispose d’un système mixte (stable et quelques packages installés depuis testing, détails ici : Mise à jour de système mixte (stretch/buster) )

Lorsque j’essaie installer virtualbox depuis testing, je suis confronté à une liste de dépendances/de packages nécessitant une mise à jour particulièrement intrigante.

root@computer apt-get -t testing install virtualbox                  
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages were automatically installed and are no longer required:
  cpp-6 libgltf-0.0-0v5 liborcus-0.11-0 libperl5.24 libwebpmux2
Use 'apt autoremove' to remove them.
The following additional packages will be installed:
  binutils binutils-common binutils-x86-64-linux-gnu coinor-libcoinmp1v5 coinor-libcoinutils3v5 cpp cpp-7 dkms fakeroot gcc gcc-7 gir1.2-rb-3.0
  hplip hplip-data libasan4 libatomic1 libbinutils libc-dev-bin libc6-dev libcamel-1.2-60 libcc1-0 libcilkrts5 libebook-1.2-19 libepubgen-0.1-1
  libfakeroot libgcc-7-dev libgcc1 libgmime-3.0-0 libgomp1 libgpgme11 libgpgmepp6 libgsoap-2.8.60 libhpmud0 libhunspell-1.6-0 libitm1 liblsan0
  libmpc3 libmpfr6 libmpx2 liborcus-0.13-0 libpython3-stdlib libquadmath0 libqxp-0.0-0 libreoffice libreoffice-avmedia-backend-gstreamer
  libreoffice-base libreoffice-base-core libreoffice-base-drivers libreoffice-calc libreoffice-common libreoffice-core libreoffice-draw
  libreoffice-evolution libreoffice-gnome libreoffice-gtk3 libreoffice-help-en-us libreoffice-help-zh-tw libreoffice-impress libreoffice-java-common
  libreoffice-l10n-zh-tw libreoffice-math libreoffice-report-builder-bin libreoffice-style-galaxy libreoffice-style-tango libreoffice-writer
  librhythmbox-core10 libsane-hpaio libsnmp30 libstaroffice-0.0-0 libtotem-plparser18 libtsan0 libubsan0 libvncserver1 libxmlsec1 libxmlsec1-nss
  libzmf-0.0-0 linux-compiler-gcc-7-x86 linux-headers-4.14.0-3-amd64 linux-headers-4.14.0-3-common linux-headers-amd64 linux-kbuild-4.14
  linux-libc-dev make manpages manpages-dev printer-driver-hpcups python3 python3-apt python3-brlapi python3-cairo python3-cups python3-dbus
  python3-distutils python3-gi python3-gi-cairo python3-lib2to3 python3-markupsafe python3-minimal python3-olefile python3-pil python3-pycurl
  python3-reportlab-accel python3-smbc python3-uno python3.6 python3.6-minimal rhythmbox rhythmbox-data rhythmbox-plugin-cdrecorder
  rhythmbox-plugins sudo uno-libs3 ure virtualbox-dkms virtualbox-qt
Suggested packages:
  binutils-doc cpp-doc gcc-7-locales python3-apport menu gcc-multilib autoconf automake libtool flex bison gdb gcc-doc gcc-7-multilib gcc-7-doc
  libgcc1-dbg libgomp1-dbg libitm1-dbg libatomic1-dbg libasan4-dbg liblsan0-dbg libtsan0-dbg libubsan0-dbg libcilkrts5-dbg libmpx2-dbg
  libquadmath0-dbg hplip-doc hplip-gui python3-notify2 system-config-printer glibc-doc gpa libreoffice-grammarcheck myspell-dictionary
  openclipart2-libreoffice | openclipart-libreoffice pstoedit unixodbc libreoffice-officebean libreoffice-report-builder libjtds-java
  libreoffice-mysql-connector | libmyodbc | libmysql-java libreoffice-sdbc-postgresql | odbc-postgresql | libpg-java libsqliteodbc | tdsodbc
  | mdbtools libreofficekit-data hunspell-dictionary-zh-tw | myspell-dictionary-zh-tw hyphen-zh-tw libreoffice-grammarcheck-zh-tw mythes-zh-tw
  tango-icon-theme fonts-crosextra-caladea fonts-crosextra-carlito make-doc python3-doc python3-tk python3-venv python3-apt-dbg python-apt-doc
  python-dbus-doc python3-dbus-dbg python-pil-doc python3-pil-dbg libcurl4-gnutls-dev python-pycurl-doc python3-pycurl-dbg python3.6-venv
  python3.6-doc binfmt-support gnome-codec-install vde2 virtualbox-guest-additions-iso
Recommended packages:
  printer-driver-postscript-hp sane-utils fonts-crosextra-caladea fonts-crosextra-carlito fonts-liberation2 fonts-linuxlibertine fonts-noto-hinted
  fonts-sil-gentium-basic libreoffice-librelogo libreoffice-nlpsolver libreoffice-ogltrans libreoffice-report-builder
  libreoffice-script-provider-bsh libreoffice-script-provider-js libreoffice-script-provider-python libreoffice-sdbc-postgresql
  libreoffice-wiki-publisher libreoffice-sdbc-hsqldb libreoffice-sdbc-firebird fonts-liberation2 | ttf-mscorefonts-installer
The following NEW packages will be installed:
  binutils-common binutils-x86-64-linux-gnu cpp-7 dkms fakeroot gcc gcc-7 libasan4 libbinutils libc-dev-bin libc6-dev libcamel-1.2-60 libcc1-0
  libcilkrts5 libebook-1.2-19 libepubgen-0.1-1 libfakeroot libgcc-7-dev libgmime-3.0-0 libgpgmepp6 libgsoap-2.8.60 libhunspell-1.6-0 libitm1
  liblsan0 libmpfr6 libmpx2 liborcus-0.13-0 libqxp-0.0-0 libreoffice-help-zh-tw libreoffice-l10n-zh-tw libreoffice-style-tango libstaroffice-0.0-0
  libtsan0 libubsan0 libvncserver1 libxmlsec1 libxmlsec1-nss libzmf-0.0-0 linux-compiler-gcc-7-x86 linux-headers-4.14.0-3-amd64
  linux-headers-4.14.0-3-common linux-headers-amd64 linux-kbuild-4.14 linux-libc-dev make manpages-dev python3-distutils python3-lib2to3
  python3-olefile python3.6 python3.6-minimal sudo virtualbox virtualbox-dkms virtualbox-qt
The following packages will be upgraded:
  binutils coinor-libcoinmp1v5 coinor-libcoinutils3v5 cpp gir1.2-rb-3.0 hplip hplip-data libatomic1 libgcc1 libgomp1 libgpgme11 libhpmud0 libmpc3
  libpython3-stdlib libquadmath0 libreoffice libreoffice-avmedia-backend-gstreamer libreoffice-base libreoffice-base-core libreoffice-base-drivers
  libreoffice-calc libreoffice-common libreoffice-core libreoffice-draw libreoffice-evolution libreoffice-gnome libreoffice-gtk3
  libreoffice-help-en-us libreoffice-impress libreoffice-java-common libreoffice-math libreoffice-report-builder-bin libreoffice-style-galaxy
  libreoffice-writer librhythmbox-core10 libsane-hpaio libsnmp30 libtotem-plparser18 manpages printer-driver-hpcups python3 python3-apt
  python3-brlapi python3-cairo python3-cups python3-dbus python3-gi python3-gi-cairo python3-markupsafe python3-minimal python3-pil python3-pycurl
  python3-reportlab-accel python3-smbc python3-uno rhythmbox rhythmbox-data rhythmbox-plugin-cdrecorder rhythmbox-plugins uno-libs3 ure
61 upgraded, 55 newly installed, 0 to remove and 1100 not upgraded.
Need to get 191 MB of archives.
After this operation, 360 MB of additional disk space will be used.
Do you want to continue? [Y/n] ^C

Une série d’entre-eux font sens (libfakeroot par exemple) mais je ne comprends pas ce que libreoffice-calc (déjà installé en version stable) ou encorerythmbox viennent faire dans cette liste.

Une idée ?

Merci d’avance pour votre aide.