inc::latest and inc::latest::private (in fact everything under inc/ in the main perl package plus the manpage for inc::latest) should be part of the Module-Build subpackage, not the main package, since they are part of the Module-Build distribution. Having them in the main perl package will cause a file conflict when a dual-lifed perl-Module-Build package is created.
This is a similar issue to the one with version::Internals in Bug #549306.
I can fix it in CVS myself if you're busy.
I'm sorry for delay. I completely missed your message.
This will be fixed in -125 in rawhide. Please next time feel free commit.