Details about Project Leonardo can be found at the project portal, http://leonardolibrary.org
The original reason of the project was to consolidate IMSLP-EU operations in such a way that the responsibility was under an organization (even though small) rather than under an individual. Then it was realized that the principle could be applicable to other similar websites, so the scope of the project was extended to "provide web hosting services to online libraries that distribute free contents in any fields of arts and science".
imslp wrote:there might be interesting things coming soon from Project Leonardo
In New Zealand copyright lasts for 50 years after the author's death. In principle, Project Leonardo may provide web hosting services to users located in New Zealand or in other "50 pma countries", so that they may lawfully upload or download scores that are public domain in their jurisdictions. This might be considered as a possibility for the future.