Nope. Any really large government data is not text -- it's mostly in older open binary formats (e.g. weather data in GRIB from NOAA) or expensive proprietary binary formats (e.g. healthcare data in SAS from CMS).

>I wonder if most of the primary sources this is intended to target (i.e. govt) ...

The second sentence on their website appears to state otherwise: "As a team we have a bias towards supporting scientific + research data use cases."

Edit: Well, on further reading they do go on to say, "What we're building isn't quite ready for prime time yet, but if you want to play around...", so perhaps I should not jump the gun :)