/usr/include/vamp-hostsdk/ is in vamp-plugin-sdk 2.6~repack0-3.
This file is owned by root:root, with mode 0o755.
..
/usr/include/vamp-hostsdk/Plugin.h
/usr/include/vamp-hostsdk/PluginBase.h
/usr/include/vamp-hostsdk/PluginBufferingAdapter.h
/usr/include/vamp-hostsdk/PluginChannelAdapter.h
/usr/include/vamp-hostsdk/PluginHostAdapter.h
/usr/include/vamp-hostsdk/PluginInputDomainAdapter.h
/usr/include/vamp-hostsdk/PluginLoader.h
/usr/include/vamp-hostsdk/PluginSummarisingAdapter.h
/usr/include/vamp-hostsdk/PluginWrapper.h
/usr/include/vamp-hostsdk/RealTime.h
/usr/include/vamp-hostsdk/host-c.h
/usr/include/vamp-hostsdk/hostguard.h
/usr/include/vamp-hostsdk/vamp-hostsdk.h