Comment 10 for bug 2051153

Just to be sure I checked removal (things should go away) and fresh install (unit should be started but empty as there is nothing from before to back up).

# removal

root@j-vm:~# apt remove -y qemu-block-extra; systemctl status run-qemu.mount; ls -laF /run/qemu/
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
The following packages were automatically installed and are no longer required:
  adwaita-icon-theme alsa-topology-conf alsa-ucm-conf at-spi2-core cpu-checker dconf-gsettings-backend dconf-service fontconfig fontconfig-config fonts-dejavu-core glib-networking glib-networking-common
  glib-networking-services gsettings-desktop-schemas gstreamer1.0-plugins-base gstreamer1.0-plugins-good gstreamer1.0-x gtk-update-icon-cache hicolor-icon-theme humanity-icon-theme ibverbs-providers ipxe-qemu
  ipxe-qemu-256k-compat-efi-roms libaa1 libasound2 libasound2-data libasyncns0 libatk-bridge2.0-0 libatk1.0-0 libatk1.0-data libatspi2.0-0 libavahi-client3 libavahi-common-data libavahi-common3 libavc1394-0
  libboost-iostreams1.74.0 libboost-thread1.74.0 libbrlapi0.8 libcaca0 libcacard0 libcairo-gobject2 libcairo2 libcdparanoia0 libcolord2 libcups2 libdatrie1 libdaxctl1 libdconf1 libdecor-0-0
  libdecor-0-plugin-1-cairo libdeflate0 libdrm-amdgpu1 libdrm-intel1 libdrm-nouveau2 libdrm-radeon1 libdv4 libepoxy0 libfdt1 libflac8 libfontconfig1 libgbm1 libgdk-pixbuf-2.0-0 libgdk-pixbuf2.0-bin
  libgdk-pixbuf2.0-common libgfapi0 libgfrpc0 libgfxdr0 libgl1 libgl1-amber-dri libgl1-mesa-dri libglapi-mesa libglusterfs0 libglvnd0 libglx-mesa0 libglx0 libgraphite2-3 libgstreamer-plugins-base1.0-0
  libgstreamer-plugins-good1.0-0 libgtk-3-0 libgtk-3-bin libgtk-3-common libharfbuzz0b libibverbs1 libiec61883-0 libiscsi7 libjack-jackd2-0 libjbig0 libjpeg-turbo8 libjpeg8 liblcms2-2 libllvm15 libmp3lame0
  libmpg123-0 libndctl6 libnl-route-3-200 libogg0 libopus0 liborc-0.4-0 libpango-1.0-0 libpangocairo-1.0-0 libpangoft2-1.0-0 libpciaccess0 libpcsclite1 libpixman-1-0 libpmem1 libpmemobj1 libproxy1v5 libpulse0
  librados2 libraw1394-11 librbd1 librdmacm1 librsvg2-2 librsvg2-common libsamplerate0 libsdl2-2.0-0 libsensors-config libsensors5 libshout3 libslirp0 libsndfile1 libsoup2.4-1 libsoup2.4-common libspeex1
  libspice-server1 libtag1v5 libtag1v5-vanilla libthai-data libthai0 libtheora0 libtiff5 libtwolame0 liburing2 libusbredirparser1 libv4l-0 libv4lconvert0 libvirglrenderer1 libvisual-0.4-0 libvorbis0a
  libvorbisenc2 libvpx7 libvte-2.91-0 libvte-2.91-common libwavpack1 libwayland-client0 libwayland-cursor0 libwayland-egl1 libwayland-server0 libwebp7 libx11-xcb1 libxcb-dri2-0 libxcb-dri3-0 libxcb-glx0
  libxcb-present0 libxcb-randr0 libxcb-render0 libxcb-shm0 libxcb-sync1 libxcb-xfixes0 libxcomposite1 libxcursor1 libxdamage1 libxfixes3 libxi6 libxinerama1 libxkbcommon0 libxrandr2 libxrender1 libxshmfence1
  libxss1 libxtst6 libxv1 libxxf86vm1 msr-tools ovmf qemu-system-common qemu-system-data qemu-system-gui qemu-system-x86 qemu-utils seabios session-migration ubuntu-mono x11-common
Use 'apt autoremove' to remove them.
The following packages will be REMOVED:
  qemu-block-extra
0 upgraded, 0 newly installed, 1 to remove and 40 not upgraded.
After this operation, 369 kB disk space will be freed.
(Reading database ... 72988 files and directories currently installed.)
Removing qemu-block-extra (1:6.2+dfsg-2ubuntu6.17) ...
○ run-qemu.mount
     Loaded: masked (Reason: Unit run-qemu.mount is masked.)
     Active: inactive (dead) since Mon 2024-02-05 10:44:17 UTC; 3s ago
        CPU: 4ms

Feb 05 10:40:29 j-vm systemd[1]: Mounting Prepare /run/qemu to allow still running qemu binaries of former builds (after package upgrades) to fallback-load modules from there...
Feb 05 10:40:29 j-vm systemd[1]: Mounted Prepare /run/qemu to allow still running qemu binaries of former builds (after package upgrades) to fallback-load modules from there.
Feb 05 10:44:17 j-vm systemd[1]: Unmounting Prepare /run/qemu to allow still running qemu binaries of former builds (after package upgrades) to fallback-load modules from there...
Feb 05 10:44:17 j-vm systemd[1]: run-qemu.mount: Deactivated successfully.
Feb 05 10:44:17 j-vm systemd[1]: Unmounted Prepare /run/qemu to allow still running qemu binaries of former builds (after package upgrades) to fallback-load modules from there.
total 0
drwxr-xr-x 2 root root 40 Feb 5 10:38 ./
drwxr-xr-x 29 root root 840 Feb 5 10:38 ../

# install

root@j-vm:~# apt install -y qemu-block-extra; systemctl status run-qemu.mount; ls -laF /run/qemu/
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
The following NEW packages will be installed:
  qemu-block-extra
0 upgraded, 1 newly installed, 0 to remove and 40 not upgraded.
Need to get 68.1 kB of archives.
After this operation, 369 kB of additional disk space will be used.
Get:1 http://archive.ubuntu.com/ubuntu jammy-proposed/main amd64 qemu-block-extra amd64 1:6.2+dfsg-2ubuntu6.17 [68.1 kB]
Fetched 68.1 kB in 0s (392 kB/s)
Selecting previously unselected package qemu-block-extra.
(Reading database ... 72979 files and directories currently installed.)
Preparing to unpack .../qemu-block-extra_1%3a6.2+dfsg-2ubuntu6.17_amd64.deb ...
Unpacking qemu-block-extra (1:6.2+dfsg-2ubuntu6.17) ...
Setting up qemu-block-extra (1:6.2+dfsg-2ubuntu6.17) ...
Scanning processes...
Scanning linux images...

Running kernel seems to be up-to-date.

No services need to be restarted.

No containers need to be restarted.

No user sessions are running outdated binaries.

No VM guests are running outdated hypervisor (qemu) binaries on this host.
● run-qemu.mount - Prepare /run/qemu to allow still running qemu binaries of former builds (after package upgrades) to fallback-load modules from there
     Loaded: loaded (/lib/systemd/system/run-qemu.mount; enabled; vendor preset: enabled)
     Active: active (mounted) since Mon 2024-02-05 10:45:19 UTC; 3s ago
      Where: /run/qemu
       What: tmpfs
      Tasks: 0 (limit: 1171)
     Memory: 8.0K
        CPU: 2ms
     CGroup: /system.slice/run-qemu.mount

Feb 05 10:45:19 j-vm systemd[1]: Mounting Prepare /run/qemu to allow still running qemu binaries of former builds (after package upgrades) to fallback-load modules from there...
Feb 05 10:45:19 j-vm systemd[1]: Mounted Prepare /run/qemu to allow still running qemu binaries of former builds (after package upgrades) to fallback-load modules from there.
total 0
drwxr-xr-x 2 root root 40 Feb 5 10:45 ./
drwxr-xr-x 29 root root 840 Feb 5 10:38 ../

That works fine as well AFAICS, setting verified