/usr/include/libappstream-glib/ is in libappstream-glib-dev 0.7.7-2.
This file is owned by root:root, with mode 0o755.
..
/usr/include/libappstream-glib/appstream-glib.h
/usr/include/libappstream-glib/as-app-builder.h
/usr/include/libappstream-glib/as-app.h
/usr/include/libappstream-glib/as-bundle.h
/usr/include/libappstream-glib/as-checksum.h
/usr/include/libappstream-glib/as-content-rating.h
/usr/include/libappstream-glib/as-enums.h
/usr/include/libappstream-glib/as-format.h
/usr/include/libappstream-glib/as-icon.h
/usr/include/libappstream-glib/as-image.h
/usr/include/libappstream-glib/as-inf.h
/usr/include/libappstream-glib/as-launchable.h
/usr/include/libappstream-glib/as-markup.h
/usr/include/libappstream-glib/as-monitor.h
/usr/include/libappstream-glib/as-node.h
/usr/include/libappstream-glib/as-problem.h
/usr/include/libappstream-glib/as-profile.h
/usr/include/libappstream-glib/as-provide.h
/usr/include/libappstream-glib/as-release.h
/usr/include/libappstream-glib/as-require.h
/usr/include/libappstream-glib/as-review.h
/usr/include/libappstream-glib/as-screenshot.h
/usr/include/libappstream-glib/as-store.h
/usr/include/libappstream-glib/as-suggest.h
/usr/include/libappstream-glib/as-tag.h
/usr/include/libappstream-glib/as-translation.h
/usr/include/libappstream-glib/as-utils.h
/usr/include/libappstream-glib/as-version.h