https://www.bleepingcomputer.com/news/microsoft/microsoft-released-windows-10-insider-update-to-build-177131002-to-test-servicing-pipeline/

Microsoft announced yesterday that they released "Cumulative Update for Windows 10 Version Next (10.0.17713.1002) (KB4345215)" to Windows Insiders in order to test the servicing pipeline. This is being done to make sure that there are no issues when they push the Insider Preview Build 17713 to Insiders in the slow ring.

Microsoft announced this minor update in an addition to their Insider build 17713 announcement.