/usr/include/subversion-1/ is in libsvn-dev 1.6.17dfsg-3ubuntu3.5.
This file is owned by root:root, with mode 0o755.
..
/usr/include/subversion-1/mod_authz_svn.h
/usr/include/subversion-1/mod_dav_svn.h
/usr/include/subversion-1/svn_auth.h
/usr/include/subversion-1/svn_base64.h
/usr/include/subversion-1/svn_checksum.h
/usr/include/subversion-1/svn_client.h
/usr/include/subversion-1/svn_cmdline.h
/usr/include/subversion-1/svn_compat.h
/usr/include/subversion-1/svn_config.h
/usr/include/subversion-1/svn_ctype.h
/usr/include/subversion-1/svn_dav.h
/usr/include/subversion-1/svn_delta.h
/usr/include/subversion-1/svn_diff.h
/usr/include/subversion-1/svn_dirent_uri.h
/usr/include/subversion-1/svn_dso.h
/usr/include/subversion-1/svn_error.h
/usr/include/subversion-1/svn_error_codes.h
/usr/include/subversion-1/svn_fs.h
/usr/include/subversion-1/svn_hash.h
/usr/include/subversion-1/svn_io.h
/usr/include/subversion-1/svn_iter.h
/usr/include/subversion-1/svn_md5.h
/usr/include/subversion-1/svn_mergeinfo.h
/usr/include/subversion-1/svn_nls.h
/usr/include/subversion-1/svn_opt.h
/usr/include/subversion-1/svn_path.h
/usr/include/subversion-1/svn_pools.h
/usr/include/subversion-1/svn_props.h
/usr/include/subversion-1/svn_quoprint.h
/usr/include/subversion-1/svn_ra.h
/usr/include/subversion-1/svn_ra_svn.h
/usr/include/subversion-1/svn_repos.h
/usr/include/subversion-1/svn_sorts.h
/usr/include/subversion-1/svn_string.h
/usr/include/subversion-1/svn_subst.h
/usr/include/subversion-1/svn_time.h
/usr/include/subversion-1/svn_types.h
/usr/include/subversion-1/svn_user.h
/usr/include/subversion-1/svn_utf.h
/usr/include/subversion-1/svn_version.h
/usr/include/subversion-1/svn_wc.h
/usr/include/subversion-1/svn_xml.h