/usr/ is in libvarnishapi-dev 3.0.5-2.
This file is owned by root:root, with mode 0o755.
..
/usr/include/
/usr/include/varnish/
/usr/lib/
/usr/lib/x86_64-linux-gnu/
/usr/lib/x86_64-linux-gnu/pkgconfig/
/usr/lib/x86_64-linux-gnu/pkgconfig/varnishapi.pc
/usr/share/
/usr/share/doc/
/usr/share/doc/libvarnishapi-dev/
/usr/share/doc/libvarnishapi-dev/copyright
/usr/include/varnish/varnishapi.h
/usr/include/varnish/vsl.h
/usr/include/varnish/vsc_fields.h
/usr/include/varnish/vsm.h
/usr/include/varnish/vsl_tags.h
/usr/include/varnish/vsc.h
/usr/include/varnish/vsc_all.h
/usr/include/varnish/vcli.h
/usr/lib/x86_64-linux-gnu/libvarnishapi.so
/usr/share/doc/libvarnishapi-dev/changelog.Debian.gz