See for features, fixes, and known issues. NOTE: This build merges SKIP AHEAD back into FAST. So, both rings will receive the same builds going forward. What this means for 19H2 (the release due this fall) is anyone’s guess. All Microsoft has said is that more will be said about 19H2 “in the coming weeks”.
from AskWoody https://www.askwoody.com/2019/windows-10-insider-preview-build-18875-20h1-released-to-fast-skip-ahead-rings/