PAUSE

Foo-1.0.tar.gz
  Foo.pm: package Foo: $VERSION = "1.0";  # indexed
  FooInternal.pm: packge FooInternal: $VERSION = "1.0"; # indexed
  FooOther.pm: package FooOther: no $VERSION; (undef) # indexed

Foo-1.01.tar.gz
  Foo.pm: package Foo: $VERSION = "1.01"; # indexed
  FooInternal.pm: package FooInternal: $VERSION = "1.0"; # indexed!
  FooOther.pm: package FooOther: no $VERSION: (undef): # indexed

if it's stable:
  prefer latest
  then sort by version
  then sort by date descending (rev chron)

if it's dev:
  sort by version
  sort by date descending (reverse chronologically)