File-Storage used to generate downloaded archives in tgz format, to then switch to zip, more user-friendly, in particular outside the Linux world (See https://openacs.org/forums/message-view?message_id=557561). To ease the transition, a couple of parameters and relative API were introduced that would allow to choose the preferred command one should use. During this reform however, default parameter values in the tcl code became inconsistent with those in the info file. Furthermore, the chosen defaults were set as absolute paths to the executable, which is not friendly to non-linux environments, or other scenarios where the "typical" Linux filesystem structure cannot be assumed (e.g. containers, MacOS...).
The only usage of this parameters/api was in fact in the download-archive vuh. In upstream codebase, no package references this file, not even the file-storage itself. Upon review, one could see that the file would also allow to specify a custom download filename via the path, which could be considered questionable. It would also execute the command in a way that once again assumes some form of Linux environment (e.g. invoking bash).
Save for the ability to customize the archive format and the anti-feature of being able to manipulate the archive filename via the path, the script largely relplicates www/download-zip, in a better shape after a few reforms hinted by e.g. penetration tools.
Given the aformentioned considerations, I have decided to make download-archive a simple redirect to download-zip. Specifying the object_id via the path will keep working, while URLs out there expecting the name to change will not fail, but the name will not be modified. The archive format will from now on be assumed to be zip.