Per this 2018 page, GNU tar seems to work with SCHILY.* encoded xattrs, but not LIBARCHIVE.* ones:

* https://mgorny.pl/articles/portability-of-tar-features.html#...

* Via: https://github.com/mxmlnkn/ratarmount/issues/145

bsdtar ≥3.7.2 apparently adds both types to its files for maximum portability:

* https://github.com/libarchive/libarchive/pull/691/files#diff...

AFAICT, bsdtar will default to "ustar" format, but will auto-switch to "pax" if needed.