This release provides the Reference Storefront source code for Sitecore Commerce 8.2.1 Update-3.
The binary Storefront installation packages are provided in the Sitecore Commerce 8.2.1 Update-3 release package from: https://dev.sitecore.net/Downloads/Sitecore_Commerce/821/Sitecore_Commerce_821_Update3.aspx
This Reference Storefront release includes bug fixes, as listed in the Sitecore Commerce 8.2.1 Update-3 release notes, available at the above link.
This release does not introduce any updates to Reference Storefront documentation.