/usr/include/stxxl/bits/containers/ is in libstxxl-dev 1.3.1-1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/stxxl/bits/containers/btree/
/usr/include/stxxl/bits/containers/btree/btree.h
/usr/include/stxxl/bits/containers/btree/iterator.h
/usr/include/stxxl/bits/containers/btree/iterator_map.h
/usr/include/stxxl/bits/containers/btree/leaf.h
/usr/include/stxxl/bits/containers/btree/node.h
/usr/include/stxxl/bits/containers/btree/node_cache.h
/usr/include/stxxl/bits/containers/btree/root_node.h
/usr/include/stxxl/bits/containers/deque.h
/usr/include/stxxl/bits/containers/map.h
/usr/include/stxxl/bits/containers/pager.h
/usr/include/stxxl/bits/containers/pq_ext_merger.h
/usr/include/stxxl/bits/containers/pq_helpers.h
/usr/include/stxxl/bits/containers/pq_losertree.h
/usr/include/stxxl/bits/containers/pq_mergers.h
/usr/include/stxxl/bits/containers/priority_queue.h
/usr/include/stxxl/bits/containers/queue.h
/usr/include/stxxl/bits/containers/stack.h
/usr/include/stxxl/bits/containers/vector.h