Every run of the pipeline records how much of each delivery day arrived against what was expected. This page summarises those records by category of data, live — when something breaks upstream, it shows here rather than quietly turning into a gap in your backtest.
Completeness is measured against the intervals expected for the latest delivery day, so a value below 100% usually means an upstream publisher hasn't released the full day yet — not that data was lost. Publishers work to their own schedules, and some series (hydro reservoir levels, for instance) are weekly rather than intraday.