/usr/include/Inventor/annex/ is in libcoin80-dev 3.1.4~abc9f50-4ubuntu2.
This file is owned by root:root, with mode 0o755.
..
/usr/include/Inventor/annex/FXViz/
/usr/include/Inventor/annex/FXViz/elements/
/usr/include/Inventor/annex/FXViz/elements/SoGLShadowCullingElement.h
/usr/include/Inventor/annex/FXViz/elements/SoShadowStyleElement.h
/usr/include/Inventor/annex/FXViz/nodes/
/usr/include/Inventor/annex/FXViz/nodes/SoShadowCulling.h
/usr/include/Inventor/annex/FXViz/nodes/SoShadowDirectionalLight.h
/usr/include/Inventor/annex/FXViz/nodes/SoShadowGroup.h
/usr/include/Inventor/annex/FXViz/nodes/SoShadowSpotLight.h
/usr/include/Inventor/annex/FXViz/nodes/SoShadowStyle.h
/usr/include/Inventor/annex/ForeignFiles/
/usr/include/Inventor/annex/ForeignFiles/SoForeignFileKit.h
/usr/include/Inventor/annex/ForeignFiles/SoSTLFileKit.h
/usr/include/Inventor/annex/HardCopy/
/usr/include/Inventor/annex/HardCopy/SoHardCopy.h
/usr/include/Inventor/annex/HardCopy/SoPSVectorOutput.h
/usr/include/Inventor/annex/HardCopy/SoVectorOutput.h
/usr/include/Inventor/annex/HardCopy/SoVectorizeAction.h
/usr/include/Inventor/annex/HardCopy/SoVectorizePSAction.h
/usr/include/Inventor/annex/Profiler/
/usr/include/Inventor/annex/Profiler/SbProfilingData.h
/usr/include/Inventor/annex/Profiler/SoProfiler.h
/usr/include/Inventor/annex/Profiler/elements/
/usr/include/Inventor/annex/Profiler/elements/SoProfilerElement.h
/usr/include/Inventor/annex/Profiler/engines/
/usr/include/Inventor/annex/Profiler/engines/SoProfilerTopEngine.h
/usr/include/Inventor/annex/Profiler/nodekits/
/usr/include/Inventor/annex/Profiler/nodekits/SoNodeVisualize.h
/usr/include/Inventor/annex/Profiler/nodekits/SoProfilerOverlayKit.h
/usr/include/Inventor/annex/Profiler/nodekits/SoProfilerTopKit.h
/usr/include/Inventor/annex/Profiler/nodekits/SoProfilerVisualizeKit.h
/usr/include/Inventor/annex/Profiler/nodekits/SoScrollingGraphKit.h
/usr/include/Inventor/annex/Profiler/nodes/
/usr/include/Inventor/annex/Profiler/nodes/SoProfilerStats.h
/usr/include/Inventor/annex/Profiler/utils/
/usr/include/Inventor/annex/Profiler/utils/SoProfilingReportGenerator.h