/usr/share/perl5/HTML/Mason/ is in libhtml-mason-perl 1:1.56-1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/perl5/HTML/Mason/Admin.pod
/usr/share/perl5/HTML/Mason/Apache/
/usr/share/perl5/HTML/Mason/Apache/Request.pm
/usr/share/perl5/HTML/Mason/ApacheHandler.pm
/usr/share/perl5/HTML/Mason/ApacheUserDirHandler.pm
/usr/share/perl5/HTML/Mason/CGIHandler.pm
/usr/share/perl5/HTML/Mason/Cache/
/usr/share/perl5/HTML/Mason/Cache/BaseCache.pm
/usr/share/perl5/HTML/Mason/Compiler/
/usr/share/perl5/HTML/Mason/Compiler.pm
/usr/share/perl5/HTML/Mason/Compiler/ToObject.pm
/usr/share/perl5/HTML/Mason/Component/
/usr/share/perl5/HTML/Mason/Component.pm
/usr/share/perl5/HTML/Mason/Component/FileBased.pm
/usr/share/perl5/HTML/Mason/Component/Subcomponent.pm
/usr/share/perl5/HTML/Mason/ComponentSource.pm
/usr/share/perl5/HTML/Mason/Devel.pod
/usr/share/perl5/HTML/Mason/Escapes.pm
/usr/share/perl5/HTML/Mason/Exceptions.pm
/usr/share/perl5/HTML/Mason/FAQ.pod
/usr/share/perl5/HTML/Mason/FakeApache.pm
/usr/share/perl5/HTML/Mason/Handler.pm
/usr/share/perl5/HTML/Mason/Interp.pm
/usr/share/perl5/HTML/Mason/Lexer.pm
/usr/share/perl5/HTML/Mason/MethodMaker.pm
/usr/share/perl5/HTML/Mason/Params.pod
/usr/share/perl5/HTML/Mason/Parser.pm
/usr/share/perl5/HTML/Mason/Plugin/
/usr/share/perl5/HTML/Mason/Plugin.pm
/usr/share/perl5/HTML/Mason/Plugin/Context.pm
/usr/share/perl5/HTML/Mason/Request.pm
/usr/share/perl5/HTML/Mason/Resolver/
/usr/share/perl5/HTML/Mason/Resolver.pm
/usr/share/perl5/HTML/Mason/Resolver/File.pm
/usr/share/perl5/HTML/Mason/Resolver/Null.pm
/usr/share/perl5/HTML/Mason/Subclassing.pod
/usr/share/perl5/HTML/Mason/Tests.pm
/usr/share/perl5/HTML/Mason/Tools.pm
/usr/share/perl5/HTML/Mason/Utils.pm