toolboxes stderr

+ python gui/wxpython/core/toolboxes.py doctest
+ python gui/wxpython/core/toolboxes.py test
m.unknown
Unable to fetch interface description for command 'm.unknown'.

Details: [Errno 2] No such file or directory
WARNING: Some addons failed when loading. Please consider to update your addons by running 'g.extension.all -f'.