How do I get an unpopular package that's needed by an existing package to extra?

Ey, A while ago I made the AUR package perl-acme-cow, which is needed for some cowfiles bundled with cowsay. Is there a process for dependencies to enter extra? I understand that it's not popular and doesn't meet the requirement, but without it, attempting to use certain bundled cowfiles results in an error. Cheers, Aᴀʀᴏɴ