/usr/share/perl5/IPC/PubSub/ is in libipc-pubsub-perl 0.29-1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/perl5/IPC/PubSub/Cache/
/usr/share/perl5/IPC/PubSub/Cache.pm
/usr/share/perl5/IPC/PubSub/Cache/DBM_Deep.pm
/usr/share/perl5/IPC/PubSub/Cache/JiftyDBI/
/usr/share/perl5/IPC/PubSub/Cache/JiftyDBI.pm
/usr/share/perl5/IPC/PubSub/Cache/JiftyDBI/Stash/
/usr/share/perl5/IPC/PubSub/Cache/JiftyDBI/Stash.pm
/usr/share/perl5/IPC/PubSub/Cache/JiftyDBI/Stash/Item.pm
/usr/share/perl5/IPC/PubSub/Cache/JiftyDBI/Stash/Publisher.pm
/usr/share/perl5/IPC/PubSub/Cache/Memcached.pm
/usr/share/perl5/IPC/PubSub/Cache/PlainHash.pm
/usr/share/perl5/IPC/PubSub/Cacheable.pm
/usr/share/perl5/IPC/PubSub/Publisher.pm
/usr/share/perl5/IPC/PubSub/Subscriber.pm