/usr/include/x86_64-linux-gnu/ is in liblttng-ust-dev 2.10.1-1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/x86_64-linux-gnu/lttng/
/usr/include/x86_64-linux-gnu/lttng/align.h
/usr/include/x86_64-linux-gnu/lttng/bug.h
/usr/include/x86_64-linux-gnu/lttng/lttng-ust-tracef.h
/usr/include/x86_64-linux-gnu/lttng/lttng-ust-tracelog.h
/usr/include/x86_64-linux-gnu/lttng/ringbuffer-abi.h
/usr/include/x86_64-linux-gnu/lttng/ringbuffer-config.h
/usr/include/x86_64-linux-gnu/lttng/tracef.h
/usr/include/x86_64-linux-gnu/lttng/tracelog.h
/usr/include/x86_64-linux-gnu/lttng/tracepoint-event.h
/usr/include/x86_64-linux-gnu/lttng/tracepoint-rcu.h
/usr/include/x86_64-linux-gnu/lttng/tracepoint-types.h
/usr/include/x86_64-linux-gnu/lttng/tracepoint.h
/usr/include/x86_64-linux-gnu/lttng/ust-abi.h
/usr/include/x86_64-linux-gnu/lttng/ust-clock.h
/usr/include/x86_64-linux-gnu/lttng/ust-compiler.h
/usr/include/x86_64-linux-gnu/lttng/ust-config.h
/usr/include/x86_64-linux-gnu/lttng/ust-ctl.h
/usr/include/x86_64-linux-gnu/lttng/ust-elf.h
/usr/include/x86_64-linux-gnu/lttng/ust-endian.h
/usr/include/x86_64-linux-gnu/lttng/ust-error.h
/usr/include/x86_64-linux-gnu/lttng/ust-events.h
/usr/include/x86_64-linux-gnu/lttng/ust-getcpu.h
/usr/include/x86_64-linux-gnu/lttng/ust-tracepoint-event-nowrite.h
/usr/include/x86_64-linux-gnu/lttng/ust-tracepoint-event-reset.h
/usr/include/x86_64-linux-gnu/lttng/ust-tracepoint-event-write.h
/usr/include/x86_64-linux-gnu/lttng/ust-tracepoint-event.h
/usr/include/x86_64-linux-gnu/lttng/ust-tracer.h
/usr/include/x86_64-linux-gnu/lttng/ust-version.h
/usr/include/x86_64-linux-gnu/lttng/ust.h