Late 2019 I had a short conversation with Abrash about a new OS for the next set of glasses and my immediate reaction was “why?” He was adamant that there was a security need which Linux could not fill (his big concern was too much surface area for exploits in the context of untrusted 3rd party code). I remember thinking that this would be a surprise to cloud engineers at the big hosters, but chose not to continue the argument. He didn’t get where he is by being dramatically wrong very often, after all, but it still struck me as a waste. Note I did not work at Meta so he may have had stronger justifications he chose not to expose.