/usr/share/doc/libgnatcoll-doc/html/_sources/ is in libgnatcoll-doc 1.6gpl2014-6.
This file is owned by root:root, with mode 0o755.
..
/usr/share/doc/libgnatcoll-doc/html/_sources/boyer_moore.txt
/usr/share/doc/libgnatcoll-doc/html/_sources/building.txt
/usr/share/doc/libgnatcoll-doc/html/_sources/config.txt
/usr/share/doc/libgnatcoll-doc/html/_sources/email.txt
/usr/share/doc/libgnatcoll-doc/html/_sources/filling.txt
/usr/share/doc/libgnatcoll-doc/html/_sources/geometry.txt
/usr/share/doc/libgnatcoll-doc/html/_sources/iconv.txt
/usr/share/doc/libgnatcoll-doc/html/_sources/index.txt
/usr/share/doc/libgnatcoll-doc/html/_sources/intro.txt
/usr/share/doc/libgnatcoll-doc/html/_sources/json.txt
/usr/share/doc/libgnatcoll-doc/html/_sources/memory.txt
/usr/share/doc/libgnatcoll-doc/html/_sources/mmap.txt
/usr/share/doc/libgnatcoll-doc/html/_sources/pools.txt
/usr/share/doc/libgnatcoll-doc/html/_sources/projects.txt
/usr/share/doc/libgnatcoll-doc/html/_sources/ravenscar.txt
/usr/share/doc/libgnatcoll-doc/html/_sources/readline.txt
/usr/share/doc/libgnatcoll-doc/html/_sources/refcount.txt
/usr/share/doc/libgnatcoll-doc/html/_sources/scripting.txt
/usr/share/doc/libgnatcoll-doc/html/_sources/sql.txt
/usr/share/doc/libgnatcoll-doc/html/_sources/storage_pools.txt
/usr/share/doc/libgnatcoll-doc/html/_sources/templates.txt
/usr/share/doc/libgnatcoll-doc/html/_sources/terminals.txt
/usr/share/doc/libgnatcoll-doc/html/_sources/traces.txt
/usr/share/doc/libgnatcoll-doc/html/_sources/tribooleans.txt
/usr/share/doc/libgnatcoll-doc/html/_sources/vfs.txt
/usr/share/doc/libgnatcoll-doc/html/_sources/xref.txt