/usr/lib/ada/ is in libgnatvsn6-dev 6.4.0-17ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/ada/adalib/
/usr/lib/ada/adalib/gnatvsn/
/usr/lib/ada/adalib/gnatvsn/alloc.ali
/usr/lib/ada/adalib/gnatvsn/aspects.ali
/usr/lib/ada/adalib/gnatvsn/atree.ali
/usr/lib/ada/adalib/gnatvsn/casing.ali
/usr/lib/ada/adalib/gnatvsn/csets.ali
/usr/lib/ada/adalib/gnatvsn/debug.ali
/usr/lib/ada/adalib/gnatvsn/einfo.ali
/usr/lib/ada/adalib/gnatvsn/elists.ali
/usr/lib/ada/adalib/gnatvsn/fname.ali
/usr/lib/ada/adalib/gnatvsn/gnatvsn.ali
/usr/lib/ada/adalib/gnatvsn/hostparm.ali
/usr/lib/ada/adalib/gnatvsn/krunch.ali
/usr/lib/ada/adalib/gnatvsn/lib.ali
/usr/lib/ada/adalib/gnatvsn/namet.ali
/usr/lib/ada/adalib/gnatvsn/nlists.ali
/usr/lib/ada/adalib/gnatvsn/opt.ali
/usr/lib/ada/adalib/gnatvsn/output.ali
/usr/lib/ada/adalib/gnatvsn/repinfo.ali
/usr/lib/ada/adalib/gnatvsn/scans.ali
/usr/lib/ada/adalib/gnatvsn/sem_aux.ali
/usr/lib/ada/adalib/gnatvsn/sinfo.ali
/usr/lib/ada/adalib/gnatvsn/sinput.ali
/usr/lib/ada/adalib/gnatvsn/snames.ali
/usr/lib/ada/adalib/gnatvsn/stand.ali
/usr/lib/ada/adalib/gnatvsn/stringt.ali
/usr/lib/ada/adalib/gnatvsn/table.ali
/usr/lib/ada/adalib/gnatvsn/tree_in.ali
/usr/lib/ada/adalib/gnatvsn/tree_io.ali
/usr/lib/ada/adalib/gnatvsn/types.ali
/usr/lib/ada/adalib/gnatvsn/uintp.ali
/usr/lib/ada/adalib/gnatvsn/uname.ali
/usr/lib/ada/adalib/gnatvsn/urealp.ali
/usr/lib/ada/adalib/gnatvsn/widechar.ali