I seem to remember that Perl modules are "objects" or collections of them

This isn't necessarily the case. Some Perl modules are object-orientated and are classes (not "objects" which are things instantiated from the classes) but equally some Perl modules are not object-orientated at all. Some (like the venerable CGI.pm) can be treated either as a class or not, depending on the calling code by having both an OO interface and a procedural interface within the same module.