The first question summary is … poor. Congressman's biggest concern after poking around on github seemed to be about international committers and a "native Nigerian" committing a lot of the code. (based on looking around the github-generated contributors pages for the libra and rust repos, I have no idea who he's talking about).

The second answer was: "This is a very technical question. We'll get back to you." Which is to be expected; there's no reason for Mr. Marcus to risk a felony by bullshitting in front of Congress about technical decisions.