This page is for downloading the base GNUstep system. To download individual applications, libraries or frameworks, see the Applications page.
Many packages should be signed. You can get the public key "gnustep-maintainer (at) gnu.org" from the GNUstep Project Keyring page. Older packages may be signed with the public key "fedor (at) gnu.org" available at the same location.
GNUstep has a GitHub Project
Page where you can get sources both using GIT or through the SVN gateway at your likening. You can "clone" or "check out" each repository at your likening as well as browse the sources online.
Here are better instructions on getting the GNUstep sources.