.pkg is probably specific to NeXT, as I haven't
heard of it under Unix.
As the name might suggest, it is a 'package' containing the
program and all it's associated files, likely to include installation
scripts and anything else needed. That then generally creates an
.app file, which is actually a directory wich includes the files but
is seen by the NeXT as being a single executable file.
-spc (And on every Unix system I've used
I've found tar ... )
Drop to the CLI on a NeXT and you'll find tar there as well.
Jeff
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