If sltar is doing the lifiting for the tar functionality, how about we provide a "tar" compatibility script with the package, which runs the pipelines as discussed?
As for file/libmagic, that is probably one of the worst pieces of software in hisory in how it works and by what kind of bugs it surfaces, like back when it prevented printing on Tuesdays on Ubuntu [0]. cheers! mar77i [0] https://bugs.launchpad.net/ubuntu/+source/cupsys/+bug/255161/comments/28