I’m not really following the progress of such things, but I sometimes wonder about option value syntax, e.g. the case here where it wanted an equal sign before the option’s value.
In contrast, ServerUtil built-in help shows a space, and I haven’t tested it using an equal.
Option formats is silent on this.
Command Line Interface CLI lays out a fairly specific layout that it thinks should be used:
duplicati-cli <command> <remote url> [arguments and options]
which I think would have avoided (or at least changed) confusion here if it had been used.
People surely debate such things, but I favor detection if it doesn’t limit legitimate usages, including ones that are not totally by-the-book (e.g. CLI book above) but are now allowed.