/usr/include/ is in audacious-dev 3.6.2-2.
This file is owned by root:root, with mode 0o755.
..
/usr/include/x86_64-linux-gnu/
/usr/include/x86_64-linux-gnu/libaudcore/
/usr/include/audacious/
/usr/include/audacious/audtag.h
/usr/include/x86_64-linux-gnu/libaudcore/audio.h
/usr/include/libaudgui/
/usr/include/libaudgui/list.h
/usr/include/libaudgui/menu.h
/usr/include/libaudgui/libaudgui-gtk.h
/usr/include/libaudgui/libaudgui.h
/usr/include/libaudcore/
/usr/include/libaudcore/interface.h
/usr/include/libaudcore/playlist.h
/usr/include/libaudcore/list.h
/usr/include/libaudcore/plugins.h
/usr/include/libaudcore/inifile.h
/usr/include/libaudcore/objects.h
/usr/include/libaudcore/multihash.h
/usr/include/libaudcore/probe.h
/usr/include/libaudcore/runtime.h
/usr/include/libaudcore/templates.h
/usr/include/libaudcore/mainloop.h
/usr/include/libaudcore/hook.h
/usr/include/libaudcore/index.h
/usr/include/libaudcore/preferences.h
/usr/include/libaudcore/drct.h
/usr/include/libaudcore/visualizer.h
/usr/include/libaudcore/i18n.h
/usr/include/libaudcore/equalizer.h
/usr/include/libaudcore/tinylock.h
/usr/include/libaudcore/tuple.h
/usr/include/libaudcore/ringbuf.h
/usr/include/libaudcore/plugin.h
/usr/include/libaudcore/audstrings.h
/usr/include/libaudcore/vfs.h
/usr/include/libaudcore/vfs_async.h