fits-guess-scale(1) on Linux
The text 21a51c3c6f20, as Debian 13 (Trixie), Debian 12 (Bookworm), Debian 11 (Bullseye), Debian 10 (Buster), Debian 9 (Stretch) shipped it. The page shows this text now.
Try to guess the scale of an image based on FITS headers.