/usr/include/dcmtk/oflog/helpers/ is in libdcmtk-dev 3.6.2-3build3.
This file is owned by root:root, with mode 0o755.
..
/usr/include/dcmtk/oflog/helpers/apndimpl.h
/usr/include/dcmtk/oflog/helpers/fileinfo.h
/usr/include/dcmtk/oflog/helpers/lloguser.h
/usr/include/dcmtk/oflog/helpers/lockfile.h
/usr/include/dcmtk/oflog/helpers/loglog.h
/usr/include/dcmtk/oflog/helpers/pointer.h
/usr/include/dcmtk/oflog/helpers/property.h
/usr/include/dcmtk/oflog/helpers/queue.h
/usr/include/dcmtk/oflog/helpers/sleep.h
/usr/include/dcmtk/oflog/helpers/snprintf.h
/usr/include/dcmtk/oflog/helpers/sockbuff.h
/usr/include/dcmtk/oflog/helpers/socket.h
/usr/include/dcmtk/oflog/helpers/strhelp.h
/usr/include/dcmtk/oflog/helpers/threadcf.h
/usr/include/dcmtk/oflog/helpers/timehelp.h