Apparently this wasn't obvious enough in the download page so:

Modpack Permissions

Yes, you may include this mod in your pack. I will not sign up on your website to give you express written permission. Just link to this page.

Official license is here: license.txt. To spare you the legalese: BSD license, do whatever you want with it, but don't sue me if it wrecks your stuff. I'd also prefer if you host it somewhere that you provide a donation link somewhere visible, but I don't require it.

Donate to keep MPS updating regularly and adfly-free!