/usr/share/code_saturne/users/base/ is in code-saturne-data 2.1.0-4ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/code_saturne/users/base/cs_user_join.c
/usr/share/code_saturne/users/base/cs_user_mesh_input.c
/usr/share/code_saturne/users/base/cs_user_mesh_modify.c
/usr/share/code_saturne/users/base/cs_user_mesh_thinwall.c
/usr/share/code_saturne/users/base/cs_user_periodicity.c
/usr/share/code_saturne/users/base/cs_user_postprocess.c
/usr/share/code_saturne/users/base/cs_user_saturne_coupling.c
/usr/share/code_saturne/users/base/cs_user_solver.c
/usr/share/code_saturne/users/base/cs_user_syrthes_coupling.c
/usr/share/code_saturne/users/base/usalcl.f90
/usr/share/code_saturne/users/base/usalin.f90
/usr/share/code_saturne/users/base/usaste.f90
/usr/share/code_saturne/users/base/usclim.f90
/usr/share/code_saturne/users/base/user_modules.f90
/usr/share/code_saturne/users/base/ushist.f90
/usr/share/code_saturne/users/base/usini1.f90
/usr/share/code_saturne/users/base/usiniv.f90
/usr/share/code_saturne/users/base/uskpdc.f90
/usr/share/code_saturne/users/base/usmpst.f90
/usr/share/code_saturne/users/base/usphyv.f90
/usr/share/code_saturne/users/base/usproj.f90
/usr/share/code_saturne/users/base/uspt1d.f90
/usr/share/code_saturne/users/base/ussmag.f90
/usr/share/code_saturne/users/base/usstru.f90
/usr/share/code_saturne/users/base/usthht.f90
/usr/share/code_saturne/users/base/ustmgr.f90
/usr/share/code_saturne/users/base/ustske.f90
/usr/share/code_saturne/users/base/ustskw.f90
/usr/share/code_saturne/users/base/ustsma.f90
/usr/share/code_saturne/users/base/ustsns.f90
/usr/share/code_saturne/users/base/ustsnv.f90
/usr/share/code_saturne/users/base/ustsri.f90
/usr/share/code_saturne/users/base/ustssa.f90
/usr/share/code_saturne/users/base/ustssc.f90
/usr/share/code_saturne/users/base/ustsv2.f90
/usr/share/code_saturne/users/base/usvima.f90
/usr/share/code_saturne/users/base/usvist.f90
/usr/share/code_saturne/users/base/usvort.f90
/usr/share/code_saturne/users/base/usvpst.f90