Re: [found the culprit]

[Stefan Monnier]

> It seems I misunderstood your original report: you wanted Z on a .tgz
> file to only uncompress it?  That indeed has been changed in Emacs 26,
> for consistency with a .tar.gz file.  I don't think it's a good idea
> to have the previous subtle difference back.

Agreed.

> I do think that Z on a compressed Tar archive, be it a .tar.gz or .tgz
> file, should not by default unpack the archive.  We could have a
> special prefix arg to request that, and by default we should just
> uncompress the file.  But that's a different issue.

FWIW, I consider ".tar.gz" (or "tar.lz", ...) as the archive format
(rather than as a combination of tar and compression): since the tar
format does not support random access anyway there's very little benefit
to having it uncompressed (unless the content can't be compressed
e.g. because it's already compressed).


        Stefan