Python wrapper of VirtualBox API under Debian Bullseye doesn't work

[Georg Fischer]

When starting vboxshell.py under Python3.9 on Debian Bullseye the following error eventuates:

test@testpc231:/$ cd /lib/virtualbox
test@testpc231:/lib/virtualbox$ python3.9 vboxshell.py 
Traceback (most recent call last):
  File "/usr/lib/virtualbox/vboxshell.py", line 3621, in <module>
    main(sys.argv)
  File "/usr/lib/virtualbox/vboxshell.py", line 3589, in main
    oVBoxMgr = VirtualBoxManager(style, params)
  File "/usr/local/lib/python3.9/dist-packages/vboxapi/__init__.py", line 989, in __init__
    self.platform = PlatformXPCOM(dPlatformParams)
  File "/usr/local/lib/python3.9/dist-packages/vboxapi/__init__.py", line 752, in __init__
    import xpcom.components
  File "/usr/lib/virtualbox/sdk/bindings/xpcom/python/xpcom/components.py", line 240, in <module>
    _shutdownObserver = xpcom.server.WrapObject(_ShutdownObserver(), interfaces.nsIObserver)
  File "/usr/lib/virtualbox/sdk/bindings/xpcom/python/xpcom/server/__init__.py", line 64, in WrapObject
    return _xpcom.WrapObject(policy( ob, iid ), iid, bWrapClient)
  File "/usr/lib/virtualbox/sdk/bindings/xpcom/python/xpcom/server/policy.py", line 161, in __init__
    raise ServerException(nsError.NS_ERROR_NO_INTERFACE)
xpcom.ServerException: 0x80004002 (NS_ERROR_NO_INTERFACE)

Testing conditions were as follows:

Setting up a fresh Debian Bullseye installation on amd64 from a debian-11.1.0-amd64-DVD-1.iso installer image with package groups "Debian desktop environment", "Xfce" and "Standard System Tools" selected. System local language is "de_DE.UTF-8".

Next installing virtualbox-6.1_6.1.26-145957~Debian~bullseye_amd64.deb by Debian package management tools of the distro from repo "deb [arch=amd64] ​https://download.virtualbox.org/virtualbox/debian bullseye contrib"

Now standard functionality (configuration of VMs, running VMs, etc) provided by the VirtualBox components and tools (hypervisor, GUI-App, VBoxManage) looks like working fine out of the box.

Unfortunately, this doesn't hold true for the Python wrapper of the API of VirtualBox. Starting vboxshell.py by the python3.9 interpreter of the distro provides the above mentioned error!