Graydon has been on Swift for a while, and there are a few other prominent Rust contributors there as well. I hope they are enjoying themselves and make good things.
Indeed, Huon Wilson and Alexis Beingessner are both at Apple now, and happily they remain active in the Rust community as well (though under no uncertain circumstances are they allowed to submit code).
I can understand why this is on HN, but as you say this is old news to most of us in Rust. For those not in the know, Graydon left Mozilla for a startup in 2013, and IIRC began at Apple in... 2015?
Many big tech companies have strict rules regarding which open source projects their employees can contribute to (e.g. AIUI Googlers have to clear every individual code contribution with their legal department, or else have the lawyers give them blanket access to contribute to a particular project), and Apple's policy is notoriously more strict than most (though I don't even know if Apple employees are allowed to confirm or deny this, thanks to NDAs).