/usr/include/JAGS/sampler/ is in jags 4.1.0-1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/JAGS/sampler/GraphView.h
/usr/include/JAGS/sampler/ImmutableSampleMethod.h
/usr/include/JAGS/sampler/ImmutableSampler.h
/usr/include/JAGS/sampler/Linear.h
/usr/include/JAGS/sampler/Metropolis.h
/usr/include/JAGS/sampler/MutableSampleMethod.h
/usr/include/JAGS/sampler/MutableSampler.h
/usr/include/JAGS/sampler/RWMetropolis.h
/usr/include/JAGS/sampler/SampleMethodNoAdapt.h
/usr/include/JAGS/sampler/Sampler.h
/usr/include/JAGS/sampler/SamplerFactory.h
/usr/include/JAGS/sampler/SingletonFactory.h
/usr/include/JAGS/sampler/SingletonGraphView.h
/usr/include/JAGS/sampler/Slicer.h
/usr/include/JAGS/sampler/StepAdapter.h
/usr/include/JAGS/sampler/TemperedMetropolis.h