Module::CoreList is a Perl module that can provide various information about the versions of Perl modules that shipped with perl interpreter releases. . It contains a hash of hashes which is keyed on the perl interpreter version, as indicated in $]. The second level hash has pairs of modules and as well as their versions. It's possible that the version of a module is unspecified, in which case it will be undef. . Other features include a hash providing ISO formatted versions of the release dates, as gleaned from perlhist, and a hash that clusters known perl releases by their major versions.