From the website:
"Fedora Legacy" refers to package fixes submitted for old versions of core packages or old releases of FedoraCore by people on an adhoc basis.
Packages in Fedora Legacy are controlled by their respective package maintainers and are subject to the acceptable use policies of the project. Packages in Fedora Legacy can be maintained by anyone who agrees to the project's policies and procedures. The steering committee can be asked to provide guidance, but has no power to remove legacy packages or material within legacy packages. However, legal issues or not following project guidelines may cause packages to lose their "Fedora Legacy" status.
Packages in Fedora Legacy must be built entirely from software meeting the open source guidelines and must be signed with the package's key rather than the Fedora key. RHN will not carry Fedora Legacy content.