Yep, they aren't pure C#, still way more relevant to the world IT infrastructure than anything Go.
The core sql server rdbms engine is hosting the .net runtime for a few things - but there its maginal compared to C++.
Modern stacks are seldom pure blood language X, thus if 5% of it is written in Y, the product is written in a mix of X and Y.
Which I also mentioned on my comment, "Yep, they aren't pure C#", naturally overseen when one intends to champion its language as "Year of Desktop Linux" on IT infrastructures.
The Linux kernel is 0.2% of shell scripts, yet no one would say it's written in shell. Same for windows or sql server. .Net is marginal there.
Btw I do code in Go, but I mostly use go apps and enjoys their small memory footprint and ease of deployment.
I must not be the only one as I see go apps pretty much everywhere in ops teams.
Fortune 500 prefer to care about actual delivered business value.
Go talk to some SRE team in F100 and F500 and ask them what they think about C# infra side lol.
The fact that C# was running on Windows only until 2 years ago explains why.
Plenty them do run production servers on Windows.
You forgot there are 498 left to check.