This CPAN module (see the URL) is required by the media-sound/squeezecenter ebuild. That ebuild is currently having to package its own copy of this CPAN module and has caused bug#251494.
This bug impacts the release of squeezeboxserver 7.4. Unfortunately, Logitec has pushed out the squeezebox (the end user device that plays music) upgrade to 7.4 which is incompatible with the earlier squeezecenter. The upshot is that the squeezebox goes into an endless upgrade/downgrade cycle since the upgrade cannot talk with squeezecenter, it then downgrades which triggers yet another upgrade. I realize Logtec could have managed this more smoothly, but meantime Gentoo does not support squeezeboxserver (which woill make everything work OK) in part becuase of this package.
Created attachment 214930 [details] dev-perl/Audio-Scan-0.56 Current ebuild for Audio-Scan. If fails its test because it relies on a patched libid3tag as described in Audio-Scan-0.56/libid3tag/README.patches.
Added with disabled tests.