I'd wager almost no one actually "understands" the Linux kernel DEFINITELY not "the Linux kernel and everything atop it" It's just not possible for one person

I'd wager almost no one actually "understands" the Linux kernel DEFINITELY not "the Linux kernel and everything atop it" It's just not possible for one person (or even a small handful of people) to "understand" the entirety of a code base that big With a big enough team, you'll get a good idea - but you'll never get to full understanding