mgavideo only contains kernel modules for tv tuning and capture with Matrox cards. It think it should be in the same category as ivtv.
I don't know what is the policy with that but I think mgavideo could be removed from portage. It's no longer maintained and it can only be used with 2.4 kernels.
I vote for removal.
/me agrees, i.e. i also vote for removing it
Removed.