yeah, based on some more digging, it looks like a test case for `date --reference` in GNU coreutils was only added a few hours ago [0] so I assume it was in response to this bug.

but I don't think that should let the uutils authors off the hook - if `--reference` wasn't implemented, that should have been an error rather than silently doing the wrong thing.

after even more Git spelunking, it looks like that problem goes all the way back to the initial "Partial implemantion of date" [1] commit from 2017 - it included support for `--reference` in the argument parsing, including the correct help text, but didn't do anything with it, not even a "TODO: Handle this option" comment like `--set` has.

0: https://github.com/coreutils/coreutils/commit/14d24f7a530f58...

1: https://github.com/uutils/coreutils/commit/41d1dfaf440eabba3...