It's a joke, based on the fact that in astronomy "metal" means anything heavier than helium, regardless of whether a chemist or physicist would call it a metal. Neon, for example, counts as a metal.
By extension, any music heavier than hydrogen or helium would also count as a metal.
---------- Post added 09-21-19 at 04:53 ---------- Previous post was 09-20-19 at 16:17 ----------
I've been mirroring old debian repositories on my main desktop for a couple of retrocomputing machines I keep around.
Just discovered that I'd somehow screwed up the permissions for the mirror. The machines it was serving files to found everything OK, but the cron job that was supposed to be keeping the mirror up to date didn't have permissions to write to anything, even its own log file.
My hypothesis is that I set up the cron job, then manually ran a mirror update to populate the mirror (rather than just waiting for the cron job to fire for the first time), and ended up running the manual update as root.
Doesn't much matter, as one of the releases I was mirroring was already archived, so I don't think anything changed in the ~4 years it took me to clue in, and the other passed into the archive in the interim, so it too had probably stopped receiving updates.
But it doesn't have to matter for me to feel like an idiot. :beathead: