I am not sure if that's caused by build issues or something else, but I get this on Arch Linux when building/running from source code:
./setup.py build
/home/....../onboard/./setup.py:55: DeprecationWarning: distutils Version classes are deprecated. Use packaging.version instead.
current_ver = version.StrictVersion(DistUtilsExtra.auto.__version__)
/home/....../onboard/./setup.py:56: DeprecationWarning: distutils Version classes are deprecated. Use packaging.version instead.
required_ver = version.StrictVersion('2.12')
removing __pycache__ directories recursively
found dconf version 0.40.0
setup.py: running pkg-config: pkg-config --libs --cflags gdk-3.0 x11 xi xtst xkbfile dconf libcanberra hunspell libudev
setup.py: -I/usr/include/gtk-3.0 -I/usr/include/pango-1.0 -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include -I/usr/include/sysprof-4 -I/usr/include/harfbuzz -I/usr/include/freetype2 -I/usr/include/libpng16 -I/usr/include/libmount -I/usr/include/blkid -I/usr/include/fribidi -I/usr/include/cairo -I/usr/include/pixman-1 -I/usr/include/gdk-pixbuf-2.0 -I/usr/include/gio-unix-2.0 -I/usr/include/cloudproviders -I/usr/include/dconf -pthread -D_REENTRANT -I/usr/include/hunspell -lgdk-3 -lz -lpangocairo-1.0 -lpango-1.0 -lharfbuzz -lgdk_pixbuf-2.0 -lcairo-gobject -lcairo -lX11 -lXi -lXtst -lxkbfile -ldconf -lgio-2.0 -lgobject-2.0 -lglib-2.0 -lcanberra -lhunspell-1.7 -ludev
WARNING: the following files are not recognized by DistUtilsExtra.auto:
Onboard/manual_tests/test_xembed
Onboard/osk/osk_audio.c
Onboard/osk/osk_click_mapper.c
Onboard/osk/osk_dconf.c
Onboard/osk/osk_devices.c
Onboard/osk/osk_hunspell.c
Onboard/osk/osk_module.c
Onboard/osk/osk_module.h
Onboard/osk/osk_struts.c
Onboard/osk/osk_udev.c
Onboard/osk/osk_uinput.c
Onboard/osk/osk_uinput.h
Onboard/osk/osk_util.c
Onboard/osk/osk_virtkey.c
Onboard/osk/osk_virtkey.h
Onboard/osk/osk_virtkey_wayland.c
Onboard/osk/osk_virtkey_wayland.h
Onboard/osk/osk_virtkey_x.c
Onboard/osk/osk_virtkey_x.h
Onboard/pypredict/README
Onboard/pypredict/lm/accent_transform.h
Onboard/pypredict/lm/gen_accent_transform
Onboard/pypredict/lm/lm.cpp
Onboard/pypredict/lm/lm.h
Onboard/pypredict/lm/lm_dynamic.cpp
Onboard/pypredict/lm/lm_dynamic.h
Onboard/pypredict/lm/lm_dynamic_cached.h
Onboard/pypredict/lm/lm_dynamic_impl.h
Onboard/pypredict/lm/lm_dynamic_kn.h
Onboard/pypredict/lm/lm_merged.cpp
Onboard/pypredict/lm/lm_merged.h
Onboard/pypredict/lm/lm_python.cpp
Onboard/pypredict/lm/lm_unigram.cpp
Onboard/pypredict/lm/lm_unigram.h
Onboard/pypredict/lm/pool_allocator.cpp
Onboard/pypredict/tools/analyze
Onboard/pypredict/tools/entropy
Onboard/pypredict/tools/filter
Onboard/pypredict/tools/ksr
Onboard/pypredict/tools/letter_frequencies
Onboard/pypredict/tools/makemodels
Onboard/pypredict/tools/model_info
Onboard/pypredict/tools/optimize
Onboard/pypredict/tools/predict
Onboard/pypredict/tools/randomize
Onboard/pypredict/tools/split_corpus
Onboard/pypredict/tools/train
code-samples/embedding.py
tools/fix_glade_ids.py
tools/gen_canonical_equivalents
tools/gen_i18n_strings
tools/gen_unicode_data
tools/install_gsettings_schema
tools/licensing
tools/xembed_socket.py
./onboard
11:40:14.108 WARNING Config: Starting in project directory, importing local packages and extensions.
Traceback (most recent call last):
File "/home/....../onboard/./onboard", line 35, in <module>
from Onboard.OnboardGtk import OnboardGtk as Onboard
File "/home/....../onboard/Onboard/OnboardGtk.py", line 48, in <module>
from Onboard.Keyboard import Keyboard
File "/home/....../onboard/Onboard/Keyboard.py", line 45, in <module>
from Onboard.KeyboardPopups import TouchFeedback
File "/home/....../onboard/Onboard/KeyboardPopups.py", line 256, in <module>
class LabelPopup(KeyboardPopupDrawable):
File "/home/....../onboard/Onboard/KeyboardPopups.py", line 264, in LabelPopup
_osk_util = osk.Util()
AttributeError: module 'Onboard.osk' has no attribute 'Util'
The package from the Arch repos works fine.