https://wccftech.com/new-windows-10-2020-insider-preview-build-is-out/

Microsoft has started to release another Preview Build from the Windows 10 2020 (20H1) branch. Since the Fast and Slow ring Insiders are currently busy finalizing the upcoming Windows 10 April 2019 Update, these Windows 10 20H1 builds are only being offered to those who had opted into Skip Ahead.

As noted previously, Microsoft has skipped working on Windows 10 1908 (19H2) to focus on 20H1 since the company said it requires a longer lead time. “We will begin releasing 19H2 bits to Insiders later this spring after we get 19H1 nearly finished and ready,” the company added.