/usr/share/doc/ is in syncache 1.2-1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/doc/syncache/
/usr/share/doc/syncache/copyright
/usr/share/doc/syncache/rdoc/
/usr/share/doc/syncache/rdoc/classes/
/usr/share/doc/syncache/rdoc/classes/SynCache.html
/usr/share/doc/syncache/rdoc/classes/SynCache/
/usr/share/doc/syncache/rdoc/classes/SynCache/CacheError.html
/usr/share/doc/syncache/rdoc/classes/SynCache/Cache.html
/usr/share/doc/syncache/rdoc/classes/SynCache/CacheEntry.html
/usr/share/doc/syncache/rdoc/classes/SynCache/RemoteCache.html
/usr/share/doc/syncache/rdoc/classes/SynCache/Placeholder.html
/usr/share/doc/syncache/rdoc/fr_file_index.html
/usr/share/doc/syncache/rdoc/index.html
/usr/share/doc/syncache/rdoc/rdoc-style.css
/usr/share/doc/syncache/rdoc/created.rid
/usr/share/doc/syncache/rdoc/fr_method_index.html
/usr/share/doc/syncache/rdoc/fr_class_index.html
/usr/share/doc/syncache/rdoc/files/
/usr/share/doc/syncache/rdoc/files/lib/
/usr/share/doc/syncache/rdoc/files/lib/syncache_rb.html
/usr/share/doc/syncache/rdoc/files/lib/syncache/
/usr/share/doc/syncache/rdoc/files/lib/syncache/syncache_rb.html
/usr/share/doc/syncache/rdoc/files/lib/syncache/remote_rb.html
/usr/share/doc/syncache/rdoc/files/README_rdoc.html
/usr/share/doc/syncache/changelog.gz
/usr/share/doc/syncache/changelog.Debian.gz
/usr/share/doc/syncache/README.rdoc