A lot of that is driver code, since so many devices are supported by mainstream. The typical user wont see anywhere near 800k new lines of code running on their systems when upgrading.
What if it's 790000 lines of new/updated tests and 10000 of new functionality?
The day a ratio anywhere close to that happens in the Linux kernel, be alert for all the flying pigs outside.
Hahaah TIL - Not a contributor, nor do i have the C skills to know what's going on in the code base to understand it
I've actually got Pink Floyd on right now, so it's not that far fetched.