Public feed for official Sitecore Platform packages
Official Sitecore NuGet Feed
Sitecore supports the NuGet package management system for distributing new Sitecore packages.
Sitecore NuGet packages are provided "as is". Support is provided on a best effort basis, without any SLA, and designed mostly for feedback.
Link to Sitecore Nuget FAQ.
Link to Sitecore Nuget License agreement.