I know it because I've worked in corporate data engineering and large data migrations and it would be abnormal to do anything else. there's a full review of test data, a scope of work, an acceptance period, etc.

You think reddit doesn't know about these utilities? You think Google doesn't?

You need to chill out and acknowledge how an industry works. I'm sure you are convinced but your idea of things isn't how the industry works.

I don't need to explain to you that the sky is blue. And I shouldn't need to explain to you that Google isn't going to accept a damaged product, and that reddit can or can't do some basic querying and timeseries manipulations.

Edit like you literally asked for a textbook.