/usr/include/xenomai/asm-nios2/ is in libxenomai-dev 2.6.4+dfsg-0.2.
This file is owned by root:root, with mode 0o755.
..
/usr/include/xenomai/asm-nios2/arith.h
/usr/include/xenomai/asm-nios2/atomic.h
/usr/include/xenomai/asm-nios2/bits/
/usr/include/xenomai/asm-nios2/bits/bind.h
/usr/include/xenomai/asm-nios2/bits/heap.h
/usr/include/xenomai/asm-nios2/bits/init.h
/usr/include/xenomai/asm-nios2/bits/intr.h
/usr/include/xenomai/asm-nios2/bits/pod.h
/usr/include/xenomai/asm-nios2/bits/sched.h
/usr/include/xenomai/asm-nios2/bits/shadow.h
/usr/include/xenomai/asm-nios2/bits/thread.h
/usr/include/xenomai/asm-nios2/bits/timer.h
/usr/include/xenomai/asm-nios2/calibration.h
/usr/include/xenomai/asm-nios2/features.h
/usr/include/xenomai/asm-nios2/fptest.h
/usr/include/xenomai/asm-nios2/hal.h
/usr/include/xenomai/asm-nios2/syscall.h
/usr/include/xenomai/asm-nios2/system.h
/usr/include/xenomai/asm-nios2/tsc.h
/usr/include/xenomai/asm-nios2/wrappers.h