My CSS file names are hashed, so there should never be a reason to use the same filename with old content.
Okay, good to know that my configuration working was only a coincidence and not by design. That was what I opened this issue to figure out: I’ve had this configuration for a while, but when I was reading the docs I couldn’t figure out why it actually worked. I guess the answer is that Netlify is using some globbing library internally today but might not tomorrow. I’ll change it when I get a chance.