https://groups.google.com/a/chromium.org/g/blink-dev/c/rjBSVWAGoHo/m/FhEGrTIkAwAJ?pli=1 Declaratively control various aspect of HTML fragments: - Sanitize them - Bring them from a separate URL (aka client side include ) - Buffer them instead of stream There s an explainer doc about how it would work here: https://github.com/WICG/declarative-partial-updates/blob/main/fragment-include-explainer.md