/usr/include/ is in libcsmith-dev 2.2.0-2+b1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/csmith/
/usr/include/csmith/csmith.h
/usr/include/csmith/csmith_minimal.h
/usr/include/csmith/platform_avr.h
/usr/include/csmith/platform_generic.h
/usr/include/csmith/platform_msp430.h
/usr/include/csmith/random_inc.h
/usr/include/csmith/safe_abbrev.h
/usr/include/csmith/safe_math.h
/usr/include/csmith/safe_math_macros.h
/usr/include/csmith/safe_math_macros_notmp.h
/usr/include/csmith/volatile_runtime.c
/usr/include/csmith/volatile_runtime.h
/usr/include/csmith/windows/
/usr/include/csmith/windows/stdint.h