There's no license included with the package. http://savannah.nongnu.org/projects/gap/ says GPL-2+, but it's not entirely clear to me if this applies also to the themes. Please clarify under what terms this package can be distributed.
Mail to upstream (Riccardo Mottola) sent.
Created attachment 347654 [details] Reply from Riccardo Mottola Reply received, confirming that everything is under GPL-2+.
+ 07 May 2013; Ulrich Müller <ulm@gentoo.org> gnustep-neos-theme-0.1.ebuild: + Fix LICENSE, GPL-2+ as clarified by upstream, bug 452416. +
Thanks for checking it ulm