This release is not the latest
This release updates BI Developer Extensions for Visual Studio 2017 to be compatible with the latest version of SSDT (15.9.0 SSDT installer, 2.8.11 SSAS extension, 2.5.6 SSRS extension, and 2.2 SSIS extension). There are a few other fixes.
This release in GitHub is intended to mark the version of code used to build the release.