The author says: "i often get email from someone reporting a bug in a module i've written. i email back, asking what version of the module it is, what version of perl on what os, and sometimes what version of some relevant third library (like xml::parser). they reply, saying "perl5". i say "i need the exact version, as reported by 'perl -v'". they tell me. and i say "i, uh, also asked about the version of my module and xml::parser [or whatever]". they say "oh yeah. it is 2.27". "is that my module or xml::parser?" "xml::parser." "ok, and what about my module's version?" "oh yeah. that's 3.11." by this time, days have passed, and what should have been a simple operation -- reporting the version of perl and relevant modules, has been needlessly complicated".

this module is for simplifying that task. if you add "use module::versions::report;" to a program (especially handy if your program is one that demonstrates a bug in some module), then when the program has finished running, you well get a report detailing all the modules in memory, and noting the version of each (for modules that defined a $version, at least).