Humans used this combination extensively for decades too. I'm no aware of any other simple way to grep both stdout and stderr from a process. (grep, or save to file, or pipe in any other way).

I found the explanation useful, about "why" it is that way. I didn't realize the & before the 1 means to tell it is the filedescriptor 1 and not a file named 1.

I've also found llms seem to love it when calling out to tools, I suppose for them having stderr interspersed messaged in their input doesn't make much difference