Pourquoi apt demande de désinstaller GIMP lors de l'installation d'ardour ?

Sous Ubuntu 19.04, j'essaie d'installer ardour, mais apt me demande de désinstaller GIMP :

$ sudo apt install ardour
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages were automatically installed and are no longer required:
  gimp-data libamd2 libass9 libbabl-0.1-0 libbs2b0 libcamd2 libccolamd2 libcholmod3 libde265-0 libflite1 libgegl-common libheif1 libmetis5 libmng2 libmypaint-1.3-0 libmypaint-common libmysofa0 libnorm1
  libpgm-5.2-0 libraw19 libumfpack5 libvidstab1.1 libzmq5
Use 'sudo apt autoremove' to remove them.
The following additional packages will be installed:
  ardour-data
Suggested packages:
  jamin
Recommended packages:
  ardour-video-timeline
The following packages will be REMOVED
  gimp gstreamer1.0-libav libavfilter7 libgegl-0.4-0 libgimp2.0 libpostproc55 libswscale5
The following NEW packages will be installed
  ardour ardour-data
0 to upgrade, 2 to newly install, 7 to remove and 1 not to upgrade.
Need to get 9,885 kB of archives.
After this operation, 20.9 MB of additional disk space will be used.
Do you want to continue? [Y/n] n

Pourquoi apt essaie-t-il de me faire désinstaller GIMP (entre autres) lorsque j'essaie d'installer ardour ?

apt-cache de la production :

$ apt-cache policy gimp gimp-data ardour
gimp:
  Installed: 2.10.8-2
  Candidate: 2.10.8-2
  Version table:
 *** 2.10.8-2 500
        500 http://gb.archive.ubuntu.com/ubuntu disco/universe amd64 Packages
        100 /var/lib/dpkg/status
gimp-data:
  Installed: 2.10.8-2
  Candidate: 2.10.8-2
  Version table:
 *** 2.10.8-2 500
        500 http://gb.archive.ubuntu.com/ubuntu disco/universe amd64 Packages
        500 http://gb.archive.ubuntu.com/ubuntu disco/universe i386 Packages
        100 /var/lib/dpkg/status
ardour:
  Installed: (none)
  Candidate: 1:5.12.0-3
  Version table:
     1:5.12.0-3 500
        500 http://gb.archive.ubuntu.com/ubuntu disco/universe amd64 Packages

Liste des dépôts :

$ grep -r ^deb /etc/apt/ --include="*.list"
/etc/apt/sources.list:deb http://gb.archive.ubuntu.com/ubuntu/ disco main restricted
/etc/apt/sources.list:deb http://archive.ubuntu.com/ubuntu/ disco-updates main restricted
/etc/apt/sources.list:deb http://gb.archive.ubuntu.com/ubuntu/ disco universe
/etc/apt/sources.list:deb http://gb.archive.ubuntu.com/ubuntu/ disco multiverse
/etc/apt/sources.list.d/google-chrome.list:deb [arch=amd64] http://dl.google.com/linux/chrome/deb/ stable main
/etc/apt/sources.list.d/spotify.list:deb http://repository.spotify.com stable non-free
/etc/apt/sources.list.d/vscode.list:deb [arch=amd64] http://packages.microsoft.com/repos/vscode stable main