This page will be a full breakdown of every data source behind this site: which source, which years, which variables, and how current the coverage is for each -- the same honesty this site applies everywhere else, at the source level instead of the figure level.
Not built yet. The matrix needs a source/coverage catalog that doesn't exist in the data warehouse yet -- there's nothing true to show here until that catalog lands, so rather than guess or approximate, this page states plainly that it isn't ready.
In the meantime: data coverage shows what's on file today, per entity type.