The CPAN-testers sometimes use developer releases of perl. This helps in two ways. First of all, it notifies authors of things that might be about to change in the next stable release of perl so that they can fix them before real users are effected. Second, it helps find freshly created bugs in bleadperl. But ordinary users don't care about that, as they only use stable releases. And so CPANdeps has grown a new feature. As well as filtering to only look at results for a particular version of perl, you can also filter to only look at stable releases. This is the default setting. If you want to include test results from developer releases of perl, you need to explicitly turn that on.
This is subtlely different from just selecting a version of perl. If you choose 5.8, for example, you would get test results from the unstable 5.8.9-to-be as well as the ones that you actually care about. If you choose 5.10.0, you would get test results for 5.10.0-patch-12345 which was very shortly before the stable release.
Also please note the new canonical hostname for CPANdeps, deps.cpantesters.org. This, and the fact that the source code is available, means that when I eventually lose interest, someone else can take over maintenance.