Somewhere I read that Apple use Linux (there own internal version) as the first target when developing their silicone, before then targeting macOS once developm

Somewhere I read that Apple use Linux (there own internal version) as the first target when developing their silicone, before then targeting macOS once development has progressed to a certain point. I can't find the article now though, surprising hard to google for. EDIT: It was a HN thread: https://news.ycombinator.com/item?id=30729731 https://news.ycombinator.com/item?id=30729731 "I find it crazy because you know they developed all this hardware with Linux. Just release the darn code." "Apple does bringup with Linux because the silicon team doesn’t necessarily want to deal with getting the Darwin team involved during validation." Worth reading the whole thread, some interesting insights and insider(?) info.