It's not a "what I think" thing, these were your literal words:
> How do you grep for it
And then how badly or well this works will depend on your build of grep and your environment variables, as the other user noted. I did not consider this, because I'd expect grep to just work with Unicode symbols like this when my stdin is set to UTF-8, which I'd further expect to always being the case in 2025, but it appears that's not an expectation one can reasonably have in the *nix world.
It was and continues to be unclear to me why you'd want to grep for the warning emoji though, since according to the article these are inserted somewhere deep in the console-visual explanations. They do not replace the slug denoting the compiler message type at the start of these, which as you said, can (still) be found by just grepping for "warning".
Oh but in the real world you vpn into a server that privately tailscales to some boxes that are hard to reach inside a factory and no one has physically touched them since 2018 at best ...
